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2. Melatonin negatively correlates with C-peptide after food intake
- Creator:
- Luboslav Stárka, Michaela Dušková, Rácz, B., Kateřina Šimůnková, Martin Hill, and Radmila Kancheva
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, endokrinologie, melatonin, peptidy, příjem potravy, metabolismus sacharidů, biorytmy, endocrinology, peptids, ingestion, sacharide metabolism, biological rhythms, C-peptid, 14, and 612
- Language:
- English
- Description:
- Melatonin plays a key role in the circadian timing system. At present, many other functions of melatonin are known. Question remains whether changes in endogenous melatonin may be associated with food intake. Hence, the levels of melatonin, C-peptide and glucose were followed during a daily regimen (16 hours) including standardized food intake using commercial kits. The diurnal profiles of the hormones and serum glucose were evaluated using ANOVA with Period and Subject as independent factors. Pearson’s correlations and using a multiple stepwise backward regression model consisting of the time factor as a polynomial, and serum C-peptide and glucose assessed the correlations between melatonin and the remaining parameters. Our results showed a significant negative correlation between melatonin and C-peptide. The profile of melatonin was physiological, decreasing after wake-up, showing minor changes during the daytime and increasing in the evening. As documented, lesser alterations were indicated in the course of the melatonin daytime profile, which may reflect periodic food intake. Food intake is not the primary factor influencing the melatonin course. While previous studies have mostly considered the protective effect of melatonin in diabetic subjects, our study brought the results suggesting food intake as a factor contributing to daytime melatonin variation in humans. However, the physiological role of melatonin association with food intake in daytime remains in question and should be further investigated., L. Stárka, M. Dušková, B. Rácz, K. Šimůnková, M. Hill, R. Kancheva., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3. Response of cortisol metabolites in the insulin tolerance test and synacthen tests
- Creator:
- Kateřina Šimůnková, Michaela Dušková, Mikuláš Kosák, Michal Kršek, Václav Hána, Hill, M., Jandikova, H., Pospíšilová, H., Šrámková, M., Bifulco, E., and Luboslav Stárka
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, kortizol, cortisol, synacthen test, cortisone, insulin tolerance test, 14, and 612
- Language:
- English
- Description:
- Determination of response of cortisol and its metabolites to different stimuli may be important for adrenal gland disorders. To date, only one metabolite, cortisone, has been followed in stimulation tests of the adrenal gland. We aimed to describe a response of cortisol metabolites to the standard short Synacthen test (HDST), insulin tolerance test (ITT), low dose Synacthen test (LDST) and medium dose Synacthen test (MDST). Sixty healthy subjects were investigated: 30 men and 30 women. Plasma for measurements of cortisol and its metabolites was obtained before and 30th and 60th min after Synacthen and insulin administration. The cut-off 500 nmol/l of cortisol was reached after stimulation in all of tests, the maximal stimulation level was reached in 60th min in all of the tests except for LDST. The response of cortisol and its metabolites at 30th and 60th min strongly correlated in all of the tests except for LDST. Cortisol and its metabolites increased after stimulation; in contrast, cortisone and its metabolites decreased. We showed that the response of the cortisol metabolites during the Synacthen tests and ITT well correlated, and the MDST showed similar response compared to HDST. The decrease in cortisone metabolites may correspond to the regeneration of cortisol from cortisone in response to stimulation test., K. Simunkova, M. Duskova, M. Kosak, M. Krsek, V. Hana, M. Hill, H. Jandikova, H. Pospisilova, M. Sramkova, E. Bifulco, L. Starka., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
4. The steroid spectrum during and after quitting smoking
- Creator:
- Jandikova, H., Michaela Dušková, Kateřina Šimůnková, Racz, B., Hill, M., Eva Králíková, Karel Vondra, and Luboslav Stárka
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, muži, odvykání kouření, predikce, testosteron, men, smoking cessation, prediction, testosterone, SHBG, 14, and 612
- Language:
- English
- Description:
- Addiction to tobacco results in an imbalance of endocrine homeostasis in both sexes. This can also have impacts on fertility problems. The male reproductive system is less susceptible than that of females, with a worsening spermiogram in smokers, the most cited effect in the literature. However, the literature is inconsistent as to the effects of smoking on steroid hormone levels in men, and there is very little data on the effects of quitting smoking in men. In this study we followed 76 men before quitting smoking, and then after 6, 12, and 24 weeks and 1 year of abstinence. We measured basic anthropomorphic data and steroid hormone levels along with steroid neuroactive metabolites using GC-MS. We demonstrate lower androgen levels in men who smoke, and these changes worsened after quitting smoking. There was a drop in SHBG already in the first week of non-smoking, and levels continued to remain low. Male smokers have lower androgen levels compared to non-smokers. The lower the initial level of androgen, the lower the likelihood of success in quitting smoking. Changes in steroid hormones proved to be a promising marker for the prediction of success in quitting smoking., H. Jandikova, M. Duskova, K. Simunkova, B. Racz, M. Hill, E. Kralikova, K. Vondra, L. Starka., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public