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Adv Clin Exp Med. 2016 Jan-Feb;25(1):11-9. doi: 10.17219/acem/28998.
An Assessment of the Number of Cariogenic Bacteria in the Saliva of Children with Chemotherapy-Induced Neutropenia
QBRI study helps for early prevention of metabolic disorders
A study that could help in the early prevention of the development of metabolic disorders has been conducted by a group of scientists led by Dr. Abdelilah Arredouani from the Diabetes Research Centre at the Qatar Biomedical Research Institute (QBRI), a research institute of Hamad bin Khalifa University, and Dr. Mario Falchi from the Department of Twin Research at Kings College in London.
The research study offers insight into the biological mechanisms behind metabolic differences and may have an impact in helping identify predictive markers of insulin resistance, diabetes, and obesity, making preventative care possible in Qatar and beyond.
The research was recently featured in the prestigious journal 'Diabetes' and concluded that individuals with low levels of a specific salivary protein, alpha-amylase, which is produced by the salivary glands and released in saliva, may cause the body’s energy production sources to switch from sugars to fatty acids.
Dr. Arredouani, one of the authors of the paper, along with colleagues from England, Italy and France arranged the study by carefully selecting two groups of healthy women for the research project: one group of women with a low level of the salivary protein and one with a high level.
By using a technique called 'metabolomics profiling,' and advanced statistical analysis methods, the scientists used serum samples from the women to compare their metabolism and gain an instantaneous snapshot of the physiology of their whole body.Their research indicated a significant difference between the metabolic profiles of the two groups.
Dr. Arredouani said that interestingly, the difference between the two groups studied seems to be due mainly to differences in the use of fatty acids.The results suggest that low levels of salivary alpha-amylase somehow reduces the uptake of glucose, the primary source of energy for the cells, and therefore the body shifts towards fatty acids usage to derive energy.
“If confirmed in bigger studies, the outcome may have clinical importance.Thus, low salivary amylase individuals who chronically ingest starch, in the form of rice for example, as is the case in the Middle East region, should eventually be considered to be at-risk of developing metabolic disorders, and therefore preventive nutritional and behavioral counseling should be provided to them.”
Dr. Omar El Agnaf, acting executive director of QBRI, added: “This QBRI-supported study furthers our aim to take an integrative and multidisciplinary approach in providing crucial insights into a key healthcare concerns in Qatar. By participating in collaborative studies like this one, we hope to continue to advance knowledge and champion the cause of fostering innovation in research.”
The research study offers insight into the biological mechanisms behind metabolic differences and may have an impact in helping identify predictive markers of insulin resistance, diabetes, and obesity, making preventative care possible in Qatar and beyond.
The research was recently featured in the prestigious journal 'Diabetes' and concluded that individuals with low levels of a specific salivary protein, alpha-amylase, which is produced by the salivary glands and released in saliva, may cause the body’s energy production sources to switch from sugars to fatty acids.
Dr. Arredouani, one of the authors of the paper, along with colleagues from England, Italy and France arranged the study by carefully selecting two groups of healthy women for the research project: one group of women with a low level of the salivary protein and one with a high level.
By using a technique called 'metabolomics profiling,' and advanced statistical analysis methods, the scientists used serum samples from the women to compare their metabolism and gain an instantaneous snapshot of the physiology of their whole body.Their research indicated a significant difference between the metabolic profiles of the two groups.
Dr. Arredouani said that interestingly, the difference between the two groups studied seems to be due mainly to differences in the use of fatty acids.The results suggest that low levels of salivary alpha-amylase somehow reduces the uptake of glucose, the primary source of energy for the cells, and therefore the body shifts towards fatty acids usage to derive energy.
“If confirmed in bigger studies, the outcome may have clinical importance.Thus, low salivary amylase individuals who chronically ingest starch, in the form of rice for example, as is the case in the Middle East region, should eventually be considered to be at-risk of developing metabolic disorders, and therefore preventive nutritional and behavioral counseling should be provided to them.”
Dr. Omar El Agnaf, acting executive director of QBRI, added: “This QBRI-supported study furthers our aim to take an integrative and multidisciplinary approach in providing crucial insights into a key healthcare concerns in Qatar. By participating in collaborative studies like this one, we hope to continue to advance knowledge and champion the cause of fostering innovation in research.”
Brown University biochip may lead to saliva glucose detector
Brown University researchers have created an experimental biochip that may one day test for miniscule levels of glucose in saliva rather than requiring diabetics to suffer repeated and painful finger pricks, lead scientist Domenico Pacifici told Mass High Tech in an interview.
The researchers used a technique called plasmonic interferometry — a convergence of nanotechnology and surface plasmonics, which explores the interaction of electrons and photons (light). Pacifici, an assistant professor in Brown’s School of Engineering in Providence, R.I., said the experimental device holds promise for other types of tests. He said surgeons already have expressed interest in the technology to check levels of cytokines, which are small cell-signaling molecules released when someone suffers an injury. By monitoring cytokine levels on a battlefield, for example, surgeons can determine the best time to operate on a patient with multiple injuries, he said.
“It could be possible to use these biochips to carry out the screening of multiple biomarkers for individual patients, all at once and in parallel, with unprecedented sensitivity,” Pacifici said. The results of the research, which resulted in a proof-of-concept biochip, were published in a recent issue of Nano Letters.
Each plasmonic interferometer — there are thousands of them per square millimeter — consists of a slit flanked by two grooves etched in a silver metal film. Changes in light intensity transmitted through the slit of each plasmonic interferometer provide information about the glucose concentration.
Some 26 million Americans have diabetes and typically check their glucose level by drawing blood, often with a pin prick to the finger tip, he said. “Finger pricks are not convenient, and compliance is a problem, especially in little kids,” Pacifici said. “Our test would be something that you put in your mouth for a few seconds, and then insert into a test machine to read it.”
A challenge for Pacifici and his fellow researchers is that glucose in human saliva is typically about 100 times less concentrated than in the blood. That is why they turned to plasmonic interferometers, which can pick up on such small concentrations.
“This is a proof of concept that plasmonic interferometers can be used to detect molecules in low concentrations, using a footprint that is 10 times smaller than a human hair,” he said. The technique could be used to detect other chemicals or substances, from anthrax to biological compounds at the same time on the same chip, he added.
To create the sensor, the researchers carved a slit about 100 nanometers wide and etched two 200 nanometer-wide grooves on either side of it. The slit captures incoming photons and confines them. The grooves scatter the incoming photons, which interact with the free electrons on the sensor’s metal surface. Those free electron-photon interactions create surface plasmon polaritons, special waves that move along the sensor’s surface until they meet the photons in the slit, like two ocean waves coming from different directions and colliding with each other. This wave interference determines the light intensity transmitted through the slit. The presence of the chemical measured on the sensor’s surface generates a change in the relative phase difference between the two surface plasmon waves, which in turn causes a change in light intensity.
The National Science Foundation and Brown funded the research. Pacifici said he is looking for more funding externally to move the project along more quickly. That could include a spinout company. Brown has filed a provisional patent on the technology.
Pacifici said he expects to develop a prototype in the next two years, and within five years to start testing the device. He and his co-workers are now building a database of the different components of saliva that will help them hone the current biochip for detecting glucose. Saliva contains about 99 percent water, but the remaining 1 percent includes various cells and glucose, so the biochip needs to be made more specific.
The researchers used a technique called plasmonic interferometry — a convergence of nanotechnology and surface plasmonics, which explores the interaction of electrons and photons (light). Pacifici, an assistant professor in Brown’s School of Engineering in Providence, R.I., said the experimental device holds promise for other types of tests. He said surgeons already have expressed interest in the technology to check levels of cytokines, which are small cell-signaling molecules released when someone suffers an injury. By monitoring cytokine levels on a battlefield, for example, surgeons can determine the best time to operate on a patient with multiple injuries, he said.
“It could be possible to use these biochips to carry out the screening of multiple biomarkers for individual patients, all at once and in parallel, with unprecedented sensitivity,” Pacifici said. The results of the research, which resulted in a proof-of-concept biochip, were published in a recent issue of Nano Letters.
Each plasmonic interferometer — there are thousands of them per square millimeter — consists of a slit flanked by two grooves etched in a silver metal film. Changes in light intensity transmitted through the slit of each plasmonic interferometer provide information about the glucose concentration.
Some 26 million Americans have diabetes and typically check their glucose level by drawing blood, often with a pin prick to the finger tip, he said. “Finger pricks are not convenient, and compliance is a problem, especially in little kids,” Pacifici said. “Our test would be something that you put in your mouth for a few seconds, and then insert into a test machine to read it.”
A challenge for Pacifici and his fellow researchers is that glucose in human saliva is typically about 100 times less concentrated than in the blood. That is why they turned to plasmonic interferometers, which can pick up on such small concentrations.
“This is a proof of concept that plasmonic interferometers can be used to detect molecules in low concentrations, using a footprint that is 10 times smaller than a human hair,” he said. The technique could be used to detect other chemicals or substances, from anthrax to biological compounds at the same time on the same chip, he added.
To create the sensor, the researchers carved a slit about 100 nanometers wide and etched two 200 nanometer-wide grooves on either side of it. The slit captures incoming photons and confines them. The grooves scatter the incoming photons, which interact with the free electrons on the sensor’s metal surface. Those free electron-photon interactions create surface plasmon polaritons, special waves that move along the sensor’s surface until they meet the photons in the slit, like two ocean waves coming from different directions and colliding with each other. This wave interference determines the light intensity transmitted through the slit. The presence of the chemical measured on the sensor’s surface generates a change in the relative phase difference between the two surface plasmon waves, which in turn causes a change in light intensity.
The National Science Foundation and Brown funded the research. Pacifici said he is looking for more funding externally to move the project along more quickly. That could include a spinout company. Brown has filed a provisional patent on the technology.
Pacifici said he expects to develop a prototype in the next two years, and within five years to start testing the device. He and his co-workers are now building a database of the different components of saliva that will help them hone the current biochip for detecting glucose. Saliva contains about 99 percent water, but the remaining 1 percent includes various cells and glucose, so the biochip needs to be made more specific.
Effect of Infancy-onset Dietary Intervention on Salivary Cholesterol of Children: a Randomized Controlled Trial
Abstract
This study investigated salivary cholesterol of children from 6 to 16 years of age in response to dietary intervention. One thousand sixty-two infants started in the prospective, randomized project. At 3 years of age, every fifth child was invited into the study (n = 178). Of these, 148 enrolled, and 86 completed the oral sub-study at 16 years of age. The intervention aimed at restricting the child’s saturated fat and cholesterol intake. Control children received no special recommendations. Every third year, paraffin-stimulated saliva samples (10.0 mL) were collected for cholesterol assays. Nutrient intakes and serum total cholesterol concentrations were regularly followed up by means of 4-day food records and blood samples. Intake of saturated fatty acids (SAFA) was lower in the intervention than in the control group (p < 0.001). Salivary cholesterol concentration increased from 1.9 (± 1.1) μmol/L at 6 years of age to 16.0 (± 9.0) μmol/L at 16 years of age. The increase was smaller in the intervention than in the control group (p < 0.001). The ratios of salivary to serum cholesterol concentrations tended to be higher in boys than in girls (p = 0.07). Thus, dietary intervention was reflected in children’s salivary cholesterol values more sensitively than in serum cholesterol values. (clinicaltrials.gov NCT00223600).
This study investigated salivary cholesterol of children from 6 to 16 years of age in response to dietary intervention. One thousand sixty-two infants started in the prospective, randomized project. At 3 years of age, every fifth child was invited into the study (n = 178). Of these, 148 enrolled, and 86 completed the oral sub-study at 16 years of age. The intervention aimed at restricting the child’s saturated fat and cholesterol intake. Control children received no special recommendations. Every third year, paraffin-stimulated saliva samples (10.0 mL) were collected for cholesterol assays. Nutrient intakes and serum total cholesterol concentrations were regularly followed up by means of 4-day food records and blood samples. Intake of saturated fatty acids (SAFA) was lower in the intervention than in the control group (p < 0.001). Salivary cholesterol concentration increased from 1.9 (± 1.1) μmol/L at 6 years of age to 16.0 (± 9.0) μmol/L at 16 years of age. The increase was smaller in the intervention than in the control group (p < 0.001). The ratios of salivary to serum cholesterol concentrations tended to be higher in boys than in girls (p = 0.07). Thus, dietary intervention was reflected in children’s salivary cholesterol values more sensitively than in serum cholesterol values. (clinicaltrials.gov NCT00223600).
The Science Behind Why We Love Ice Cream
Why people prefer certain foods over others depends largely on a combination of taste and texture. While taste sensations are fairly well understood, scientists are just beginning to unravel the mystery of food texture.
Now, researchers at the Monell Chemical Senses Center in Philadelphia have found that an enzyme in saliva called amylase, which breaks down starch into liquid, could play a key role in determining the appeal of various textures of food. A new genetic study shows that people produce strikingly different amounts of amylase, and that the more of the enzyme people have in their mouth the faster they can liquefy starchy foods.
Scientists think this finding could help explain why people experience foods as creamy or slimy, sticky or watery, and that this perception could affect our preference for foods. For the numerous foods that contain starch, including pudding, sauces and even maple syrup, what can feel just right to some people is experienced as too runny or not melting enough for others because they produce different amounts of the enzyme.
The ability to quickly break down starch, which is a type of carbohydrate, is only one part of the puzzle that determines what people like to eat. Taste preferences are driven by a complicated interaction between taste buds and other receptors in the mouth and nose, and the messages they send to the brain. Culture plays a role, as people tend to like foods that are familiar, says Rick Mattes, a foods and nutrition professor at Purdue University in West Lafayette, Ind. And repetition sometimes can win out: Many people initially don't like oysters because of their slimy texture, for instance, but can come to enjoy them after several tries.
"We all have had the experience of liking a food that someone else complains is too tacky, or slippery, or gritty, or pulpy," says Paul Breslin, a researcher at the Monell center and a professor at Rutgers University in New Brunswick, N.J. "This is why a given line of product often comes in different textural forms," such as orange juice with and without pulp, he says.
Starch comprises or is added to about 60% of the foods people typically eat, so determining how it is digested is key to understanding food-texture preferences, Monell center scientists say. Other research has shown that people have a preference for creamy sensations as well as for foods that start off solid and melt in the mouth such as ice cream and chocolate, says Dr. Breslin, who began the current research because of his interest in creaminess. Amylase also could help explain individual preferences for different brands of ice cream or yogurt, for instance, because they contain different amounts of added starch.
In their recent work, Monell researchers had 73 adults swirl around in their mouths solutions made up of different concentrations of starch—blobs of translucent gelatinous substances with no particular taste—and rate their runniness over the course of 60 seconds. Depending on the amount of amylase individuals produced, the starch could be reduced to liquid within seconds.
The researchers also took DNA samples of the participants from a blood sample or cheek swab and studied the link between the numbers of copies of a gene that turns on the production of amylase and how quickly the participant reported the sample turned runny. The findings showed that the number of copies of the gene, called AMY1, varied widely between individuals. People with higher numbers of gene copies reported that the starch turned to liquid more quickly. The study was published last month in PLoS ONE, a journal of the Public Library of Science.
The Monell researchers are now investigating whether people with more AMY1 copies see larger spikes in blood glucose after eating. They also plan to study the link between greater amylase production and food preferences, hypothesizing that people who make more of the enzyme will prefer starchy products because they get a faster blast of glucose into their bloodstream.
The role of amylase and the rate of starch breakdown also has implications for diabetes. People who digest starch quickly could be more likely to have larger spikes in blood-sugar levels and thus a need for the body to generate more insulin. This continued demand on the body might lead these people to become insulin resistant or even diabetic if the body's ability to produce insulin breaks down, says Abigail Mandel, Dr. Breslin's colleague at Monell and first author on the study.
Amylase and other enzymes in saliva could also help explain food-texture preferences that are known to vary with age, Dr. Breslin says. For instance, many young children dislike certain fruits because of a perceived sliminess—think of the inside of a tomato. But people's saliva-flow rate tends to slow with age, which might affect their ability to break down starch in the mouth and reduce sensations of sliminess.
Another factor in food preferences: People vary—probably based on genetics—in their ability to detect other textures, such as fat, and bitter and sweet tastes. Valerie Duffy, a registered dietitian and professor in the department of allied health science at the University of Connecticut, Storrs, Conn., has shown in her research that adults with a gene that makes bitter tastes more intense consume fewer vegetables containing bitter compounds, such as kale or spinach.
But that genetic preference can be changed by repeatedly exposing the individual to the taste or by masking the bitterness, even at an early age, she has found. In a preliminary study with preschoolers, Dr. Duffy's group added a sweet taste to balance out the bitterness of certain vegetables—less than half a teaspoon of sugar to a cup of broccoli or asparagus, for example, during cooking—and found that the children were more accepting of the greens. Even when the sweetness was removed, the children still liked the vegetables more than before because they had developed a positive association with them, she says. "It suggests that people should focus on what they like to eat and make it work for them," Dr. Duffy says.
Now, researchers at the Monell Chemical Senses Center in Philadelphia have found that an enzyme in saliva called amylase, which breaks down starch into liquid, could play a key role in determining the appeal of various textures of food. A new genetic study shows that people produce strikingly different amounts of amylase, and that the more of the enzyme people have in their mouth the faster they can liquefy starchy foods.
Scientists think this finding could help explain why people experience foods as creamy or slimy, sticky or watery, and that this perception could affect our preference for foods. For the numerous foods that contain starch, including pudding, sauces and even maple syrup, what can feel just right to some people is experienced as too runny or not melting enough for others because they produce different amounts of the enzyme.
The ability to quickly break down starch, which is a type of carbohydrate, is only one part of the puzzle that determines what people like to eat. Taste preferences are driven by a complicated interaction between taste buds and other receptors in the mouth and nose, and the messages they send to the brain. Culture plays a role, as people tend to like foods that are familiar, says Rick Mattes, a foods and nutrition professor at Purdue University in West Lafayette, Ind. And repetition sometimes can win out: Many people initially don't like oysters because of their slimy texture, for instance, but can come to enjoy them after several tries.
"We all have had the experience of liking a food that someone else complains is too tacky, or slippery, or gritty, or pulpy," says Paul Breslin, a researcher at the Monell center and a professor at Rutgers University in New Brunswick, N.J. "This is why a given line of product often comes in different textural forms," such as orange juice with and without pulp, he says.
Starch comprises or is added to about 60% of the foods people typically eat, so determining how it is digested is key to understanding food-texture preferences, Monell center scientists say. Other research has shown that people have a preference for creamy sensations as well as for foods that start off solid and melt in the mouth such as ice cream and chocolate, says Dr. Breslin, who began the current research because of his interest in creaminess. Amylase also could help explain individual preferences for different brands of ice cream or yogurt, for instance, because they contain different amounts of added starch.
In their recent work, Monell researchers had 73 adults swirl around in their mouths solutions made up of different concentrations of starch—blobs of translucent gelatinous substances with no particular taste—and rate their runniness over the course of 60 seconds. Depending on the amount of amylase individuals produced, the starch could be reduced to liquid within seconds.
The researchers also took DNA samples of the participants from a blood sample or cheek swab and studied the link between the numbers of copies of a gene that turns on the production of amylase and how quickly the participant reported the sample turned runny. The findings showed that the number of copies of the gene, called AMY1, varied widely between individuals. People with higher numbers of gene copies reported that the starch turned to liquid more quickly. The study was published last month in PLoS ONE, a journal of the Public Library of Science.
The Monell researchers are now investigating whether people with more AMY1 copies see larger spikes in blood glucose after eating. They also plan to study the link between greater amylase production and food preferences, hypothesizing that people who make more of the enzyme will prefer starchy products because they get a faster blast of glucose into their bloodstream.
The role of amylase and the rate of starch breakdown also has implications for diabetes. People who digest starch quickly could be more likely to have larger spikes in blood-sugar levels and thus a need for the body to generate more insulin. This continued demand on the body might lead these people to become insulin resistant or even diabetic if the body's ability to produce insulin breaks down, says Abigail Mandel, Dr. Breslin's colleague at Monell and first author on the study.
Amylase and other enzymes in saliva could also help explain food-texture preferences that are known to vary with age, Dr. Breslin says. For instance, many young children dislike certain fruits because of a perceived sliminess—think of the inside of a tomato. But people's saliva-flow rate tends to slow with age, which might affect their ability to break down starch in the mouth and reduce sensations of sliminess.
Another factor in food preferences: People vary—probably based on genetics—in their ability to detect other textures, such as fat, and bitter and sweet tastes. Valerie Duffy, a registered dietitian and professor in the department of allied health science at the University of Connecticut, Storrs, Conn., has shown in her research that adults with a gene that makes bitter tastes more intense consume fewer vegetables containing bitter compounds, such as kale or spinach.
But that genetic preference can be changed by repeatedly exposing the individual to the taste or by masking the bitterness, even at an early age, she has found. In a preliminary study with preschoolers, Dr. Duffy's group added a sweet taste to balance out the bitterness of certain vegetables—less than half a teaspoon of sugar to a cup of broccoli or asparagus, for example, during cooking—and found that the children were more accepting of the greens. Even when the sweetness was removed, the children still liked the vegetables more than before because they had developed a positive association with them, she says. "It suggests that people should focus on what they like to eat and make it work for them," Dr. Duffy says.
Comparative Human Salivary and Plasma Proteomes.
Abstract
The protein compositions, or the proteomes, found in human salivary and plasma fluids are compared. From recent experimental work by many laboratories, a catalogue of 2290 proteins found in whole saliva has been compiled. This list of salivary proteins is compared with the 2698 proteins found in plasma. Approximately 27% of the whole-saliva proteins are found in plasma. However, despite this apparent low degree of overlap, the distribution found across Gene Ontological categories, such as molecular function, biological processes, and cellular components, shows significant similarities.
Moreover, nearly 40% of the proteins that have been suggested to be candidate markers for diseases such as cancer, cardiovascular disease, and stroke can be found in whole saliva. These comparisons and correlations should encourage researchers to consider the use of saliva to discover new protein markers of disease and as a diagnostic non-proximal fluid to detect early signs of disease throughout the body.
Loo JA, Yan W, Ramachandran P, Wong DT.
The protein compositions, or the proteomes, found in human salivary and plasma fluids are compared. From recent experimental work by many laboratories, a catalogue of 2290 proteins found in whole saliva has been compiled. This list of salivary proteins is compared with the 2698 proteins found in plasma. Approximately 27% of the whole-saliva proteins are found in plasma. However, despite this apparent low degree of overlap, the distribution found across Gene Ontological categories, such as molecular function, biological processes, and cellular components, shows significant similarities.
Moreover, nearly 40% of the proteins that have been suggested to be candidate markers for diseases such as cancer, cardiovascular disease, and stroke can be found in whole saliva. These comparisons and correlations should encourage researchers to consider the use of saliva to discover new protein markers of disease and as a diagnostic non-proximal fluid to detect early signs of disease throughout the body.
Loo JA, Yan W, Ramachandran P, Wong DT.
Salivary testosterone, cortisol, and progesterone: Two-week stability, interhormone correlations, and effects of time of day, menstrual cycle, and ora
Abstract
With salivary assessment of steroid hormones increasing, more work is needed to address fundamental properties of steroid hormone levels in humans. Using a test–retest design and radioimmunoassay assessment of salivary steroids, we tested the reliability of testosterone, cortisol, and progesterone levels across two weeks, as well as the effects of oral contraceptives, menstrual cycle phase, and time of day on steroid hormone levels.
Testosterone and cortisol were found to be highly reliable in both sexes. Progesterone was found to be reliable after collapsing across sex. Oral contraceptive use was associated with lower levels of testosterone, but did not affect cortisol.
Contrary to expectations, oral contraceptives also did not affect progesterone. Menstrual cycle was found to affect levels of progesterone, but not testosterone or cortisol. Time of day had an effect on cortisol, on progesterone only at one testing time, and no effect on testosterone. We explored the interhormone correlations among testosterone, progesterone, and cortisol. All three hormones were positively correlated with one another in men. In women, progesterone was positively correlated with testosterone and cortisol, but testosterone and cortisol were uncorrelated.
Scott H. Lieninga, , , Steven J. Stantonb, Ekjyot K. Sainic and Oliver C. Schultheissd
a Department of Psychology, University of Texas at Austin, 1 University Station A8000, Austin, TX 78705, USA
b Duke University, USA
c University of Michigan, Ann Arbor, USA
d Friedrich-Alexander University, Erlangen, Germany
With salivary assessment of steroid hormones increasing, more work is needed to address fundamental properties of steroid hormone levels in humans. Using a test–retest design and radioimmunoassay assessment of salivary steroids, we tested the reliability of testosterone, cortisol, and progesterone levels across two weeks, as well as the effects of oral contraceptives, menstrual cycle phase, and time of day on steroid hormone levels.
Testosterone and cortisol were found to be highly reliable in both sexes. Progesterone was found to be reliable after collapsing across sex. Oral contraceptive use was associated with lower levels of testosterone, but did not affect cortisol.
Contrary to expectations, oral contraceptives also did not affect progesterone. Menstrual cycle was found to affect levels of progesterone, but not testosterone or cortisol. Time of day had an effect on cortisol, on progesterone only at one testing time, and no effect on testosterone. We explored the interhormone correlations among testosterone, progesterone, and cortisol. All three hormones were positively correlated with one another in men. In women, progesterone was positively correlated with testosterone and cortisol, but testosterone and cortisol were uncorrelated.
Scott H. Lieninga, , , Steven J. Stantonb, Ekjyot K. Sainic and Oliver C. Schultheissd
a Department of Psychology, University of Texas at Austin, 1 University Station A8000, Austin, TX 78705, USA
b Duke University, USA
c University of Michigan, Ann Arbor, USA
d Friedrich-Alexander University, Erlangen, Germany
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