Monika Sramkova

The Role of Taste in Cephalic Phase of Insulin Secretion

The effect of a short gustatory signal of a sweet solution was tested on 15 young male volunteers. The experiment consisted of mouth rinsing with either a sucrose or aspartate solution or pure water as a placebo. Blood was then taken in short intervals of 0, 5, 10, 15 and 20 min. Blood glucose, C-peptide, insulin and cortisol were determined. While C-peptide and glucose were unaffected, a short-term increase in insulin was observed after the sucrose, but not after the aspartate or placebo. The increase in insulin was significant, though it amounted to only 0.5 mIU/l and lasted approx. 15 min reaching then the starting value. The decline of cortisol level within 20 min of the experiment was approx. 40 nmol/l, although it was also observed after aspartate or placebo mouth rinsing and was probably caused by stress factors or anticipation. In conclusion, the contribution of taste to the cephalic phase of insulin secretion is small yet significant, and mouth rinsing with 5% sucrose causes an insulin increase of just under 1 IU/l, which returns to starting level within 15 min.

The role of steroids in the prediction of affective disorders in adult men

Objective: Anxiety and mood disorders (AMD) are the most frequent mental disorders in the human population. They have recently shown increasing prevalence, and commonly disrupt personal and working lives. The aim of our study was to analyze the spectrum of circulating steroids in order to discover differences that could potentially be markers of affective depression or anxiety, and identify which steroids could be a predictive component for these diseases. Methods: We studied the steroid metabolome including 47 analytes in 20 men with depression (group D), 20 men with anxiety (group AN) and 30 healthy controls. OPLS and multivariate regression models were used for statistical analysis. Results: Discrimination of group D from controls by the OPLS method was absolute, as was group AN from controls (sensitivity = 1.000 (0.839, 1.000), specificity = 1.000 (0.887, 1.000)). Relatively good predictivity was also found for discrimination between group D from AN (sensitivity = 0.850 (0.640, 0.948), specificity = 0.900 (0.699, 0.972)). Conclusion: Selected circulating steroids, including those that are neuroactive and neuroprotective, can be useful tools for discriminating between these affective diseases in adult men.

A Comparison of Salivary Steroid Levels during Diagnostic Tests for Adrenal Insufficiency

Numerous diagnostic tests are used to evaluate the hypothalamic-pituitary-adrenal axis (HPA axis). The gold standard is still considered the insulin tolerance test (ITT), but this test has many limitations. Current guidelines therefore recommend the Synacthen test first when an HPA axis insufficiency is suspected. However, the dose of Synacthen that is diagnostically most accurate and sensitive is still a matter of debate. We investigated 15 healthy men with mean/median age 27.4/26 (SD±4.8) years, and mean/median BMI (body mass index) 25.38/24.82 (SD±3.2) kg/m2. All subjects underwent 4 dynamic tests of the HPA axis, specifically 1 μg, 10 μg, and 250 μg Synacthen (ACTH) tests and an ITT. Salivary cortisol, cortisone, pregnenolone, and DHEA (dehydroepiandrosterone) were analysed using liquid chromatography-tandem mass spectrometry. During the ITT maximum salivary cortisol levels over 12.5 nmol/l were found at 60 minutes. Maximum cortisol levels in all of the Synacthen tests were higher than this; however, demonstrating that sufficient stimulation of the adrenal glands was achieved. Cortisone reacted similarly as cortisol, i.e. we did not find any change in the ratio of cortisol to cortisone. Pregnenolone and DHEA were higher during the ITT, and their peaks preceded the cortisol peak. There was no increase of pregnenolone or DHEA in any of the Synacthen tests. We demonstrate that the 10 μg Synacthen dose is sufficient stimulus for testing the HPA axis and is also a safe and cost-effective alternative. This dose also largely eliminates both false negative and false positive results.

Daily Profiles of Dehydroepiandrosterone and Its Hydroxylated Metabolites with Respect to Food Intake

Eight women of reproductive age with normal body mass index were given 5 standardised meals, and their hormonal milieu was determined during the course of the day. Plasma from 12 withdrawals was analysed for dehydroepiandrosterone and its 7- and 16-hydroxylated metabolites. Overall, there was a maximum in the levels of steroid hormones in the morning, followed by decreases throughout the day. There was also an additional significant decrease found for dehydroepiandrosterone and its 7α-hydroxyderivative in association with the consumption of main meals, but not for the 7β-isomer or 16α-hydroxyderivative.

The Response of C19 Δ5-steroids to ACTH Stimulation and Hypoglycemia in Insulin Tolerance Test for Adrenal Insufficiency.

Studies on the time course of ACTH- or insulin-induced hypoglycemia stimulating adrenal androgens are usually limited to dehydroepiandrosterone and/or its sulphate. Our data on dehydroepiandrosterone (DHEA) and its hydroxylated metabolites clearly show that measurements of DHEA and its sulphate (DHEAS) are valuable markers of the integrity of the HPA (hypothalamus-pituitary-adrenal) axis. Assessments of HPA function should rely on measurements of baseline and/or stimulated serum cortisol concentrations, and C19 Δ5-steroids may provide additional information. The art of stimulation of 7- and 16-hydroxylated metabolites of DHEA can help our understanding of the formation sequence of these compounds.

The response of C19- and some C21-steroids during Synacthen and insulin tolerance test

HighlightsThe response of steroid metabolites might be also a marker of adrenal activity.Various dose Synacthen tests implicate earlier or later maximal steroids response.Decrease of steroid conjugates by hypoglycaemia in first 20 min of the test.Conjugated steroids present a stock for rapid conversion to free ones during stress. Abstract Testing of the adrenal function with ACTH 1–24 (Synacthen test) or insulin (insulin tolerance test‐ITT) is commonly used. The question of ongoing debate is the dose of Synacthen. Moreover, it may be important from the physiological point of view besides measurement of cortisol levels and 17&agr;‐hydroxy‐progesterone to know also the response of other steroids to these test. The plasma levels of 24 free steroids and their polar conjugates were followed after stimulation of 1 &mgr;g, 10 &mgr;g and 250 &mgr;g of ACTH 1–24 and after insulin administration in thirteen healthy subjects. The study aimed to describe a response of steroid metabolome to various doses of ACTH 1–24 and to find the equivalency of these tests. The additional ambition was to contribute to understanding of physiology of these stimulation tests and suggest an additional marker for HPA axis evaluation. No increase of most conjugated steroids and even decrease of some of them during all of the Synacthen tests and ITT at 60th min were observed. The levels of steroid conjugates decreased in ITT but did not during all of the Synacthen tests by 20 min of each test. Testosterone and estradiol did not increase during the Synacthen tests or ITT as expected. The results suggest that the conjugated steroids in the circulation can serve as reserve stock for rapid conversion into free steroids in the first minutes of the stress situation. Various doses of ACTH 1–24 used in the Synacthen tests implicate earlier or later occurrence of maximal response of stimulated steroids. The equivalent dose to ITT and standard 250 &mgr;g of ACTH 1–24 seemed to be dose of 10 &mgr;g ACTH 1–24 producing the similar response in all of the steroids in the 60th min of the test.

Physiological changes of adipokines during the menstrual cycle

Background . The cyclical effects of hormones during the menstrual cycle (MC) are responsible for driving ovulation. The information about roles of adipokines within the scope of MC are not definite. Leptin plays a role in sexual function and regulating the onset of puberty. Thin girls often fail to ovulate or release an egg from an ovary during menstruation cycles. Leptin also acts on specific receptors in the hypothalamus to inhibit appetite. Levels of leptin are increased in women suffering from premenstrual syndrome. Aim . The aim of our study was to describe physiological changes of selected steroids and adipokines at healthy women during the MC. Methods. Twenty-seven women with regular menstrual cycles were included in the study. Each sample was collected in cooled EDTA tubes, centrifuged at 2000 rpm in a refrigerated centrifuge, and stored at –80 °C. For all samples we measured luteinizing hormone (LH), follicularstimulating hormone (FSH), sex hormone-binding globulin (SHBG), testosterone, dehydroepiandrosterone (DHEA), estradiol, 7 α -DHEA, 7 β -DHEA, 7-oxoDHEA, 17-hydroxyprogesterone (17-OH P), progesterone, cortisol, adrenocorticotropic hormone (ACTH) by RIA and IRMA. Levels in plasma of hormones associated with food intake (c-peptide, ghreline, GIP, GLP, GLP-1, glucagon, insulin, leptin, PAI-1, resistin and visfatin) were measured using magnetic bead-based multiple assays (x-MAP technology, Luminex Corporation). Two kits were used: the 10-plex Bio-Plex Pro Human Diabetes assay and the 2-plex Bio-Plex Pro Human Adiponectin and Adipsin assay (both Bio-Rad Laboratories). Patient . Twenty-seven women with regular menstrual cycles (cycle length 28±2 days) were included in the study. The average age of the women was 31.8±3.56, and average BMI 22.9±2.8. The women used no hormonal contraceptives or other medicines influencing the production of steroid hormones, and were non-smokers. Before enrollment in the study, all signed informed consent that was approved by the local ethical committee of the Institute of Endocrinology. Intervention . Fasting blood samples were taken in the morning between 7 and 8 am. The first sampling was done at the start of the menstrual cycle (1st or 2nd day). Subsequent samples were taken at regular intervals every three days, for a total of 10 samples taken during the study. Main outcome measures. During the MC we found increased levels of testosterone, estradiol, progesterone, and 17-hydroxyprogesterone during ovulation. SHBG gradually increased after ovulation. There was a significant decrease in resistin levels during ovulation, followed by an increase in the latter part of the cycle. Adipsin showed a notable increase during ovulation, but this increase was not statistically significant. Results . Classical changes in gonadotropins, estrogens and progesterone during the menstrual cycle are accompanied by less striking but significant changes in 17-hydroxyprogesterone and testosterone. No significant changes show dehydroepiandrosterone and its 7-oxygenated metabolites. Adipokines show a tendency to increase during ovulation, while ghrelin and resistin decrease. There is also a remarkable association of sex hormone binging globuline (SHBG) on the day of the cycle. Conclusions . Our results demonstrate that changes to adipokines during the menstrual cycle are not substantial. Differing leptin levels are characteristic for premenstrual syndrome. Precise descriptions of physiological changes in healthy women are important in helping us understand the significance of the changes accompanying various pathological states.