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F. A. Leidenberger

Bio: F. A. Leidenberger is an academic researcher. The author has contributed to research in topics: Morning & Evening. The author has an hindex of 1, co-authored 1 publications receiving 40 citations.
Topics: Morning, Evening, Melatonin, Prolactin

Papers
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Journal ArticleDOI
TL;DR: Evidence is provided for melatonin controlling the nocturnal increase of prolactin via its ability to stimulate prolactIn release and oral administration of 6 mg melatonin significantly stimulated prolact in release above concentrations measured after placebo administration in both the morning and evening time periods.
Abstract: The relationship between the concentrations of melatonin and prolactin over the 24-h cycle has been investigated in a group of young men at three times in the year. Melatonin and prolactin showed a significant positive correlation (P less than 0.001) for all times during the 24-h period but with a greater contribution from concentrations during the nocturnal period, when both hormones were elevated. The positive correlation for nocturnal concentrations was evident in February and March (P less than 0.01) but was of greatest significance in June (P less than 0.001). In blood samples taken at 15-min intervals during the morning (0800-1200) and evening (2000-2400), melatonin and prolactin concentrations were not significantly correlated. Melatonin concentrations increased before prolactin during the evening and decreased before prolactin in the morning. Oral administration of 6 mg melatonin significantly stimulated prolactin release above concentrations measured after placebo administration, in both the morning (P less than 0.05) and evening (P less than 0.01) time periods; the prolactin response being greater in the evening. These results provide evidence for melatonin controlling the nocturnal increase of prolactin via its ability to stimulate prolactin release.

43 citations


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TL;DR: Whether the potent melatonin agonist agomelatine (S‐20098) is capable of phase‐shifting overt circadian rhythms in older adults is investigated.
Abstract: Summary Objective Older adults are less responsive to the phase-shifting effects of light than younger subjects and may have difficulties adapting to abrupt time shifts. This study aims to determine whether the potent melatonin agonist agomelatine (S-20098) is capable of phase-shifting overt circadian rhythms in older adults. Subjects and design Eight healthy elderly men participated in a double-blind, two-period, cross-over study of 15 days of daily administration of either agomelatine (50 mg) or placebo at 1830 h. Measurements At the end of each treatment period, the 24-h profiles of body temperature and of the plasma levels of GH, PRL, cortisol and TSH were collected and sleep was monitored polygraphically. Results Phase-advances, averaging nearly 2 h, were observed for the temperature profile and for the variables characterizing the temporal organization of cortisol secretion following agomelatine administration. A similar trend was observed for the circadian rise of plasma TSH. There was no effect of agomelatine on any of the sleep variables. Agomelatine stimulated GH secretion during the wake period and was associated with a transient elevation of PRL levels. Conclusions Melatonin agonists such as agomelatine may be useful to phase-shift at least some overt circadian rhythms in older adults.

173 citations

Journal ArticleDOI
Robert T. Rubin1, E K Heist, S S McGeoy, K Hanada, Ira M. Lesser 
TL;DR: The melatonin measures were not consistently related to any of the previously reported hypothalamic-pituitary-adrenal cortical axis measures in these subjects, and failed to confirm a "low melatonin syndrome" or an inverse relationship between nocturnal melatonin andnocturnal cortisol concentrations in depression.
Abstract: To ascertain the extent of dysregulation of melatonin secretion in endogenous depression, we measured nocturnal and diurnal serum melatonin concentrations in 38 depressed patients (23 women and 15 men) who had primary, definite endogenous depression according to the Research Diagnostic Criteria and in 38 individually matched normal control subjects. Previous reports have suggested that such patients may have reduced nocturnal melatonin secretion, often in conjunction with increased hypothalamic-pituitary-adrenal cortical axis activity. This has been considered as a possible reflection of reduced noradrenergic activity in depression. Compared with their matched controls, the depressed patients showed a trend toward a significantly elevated average nocturnal melatonin concentration that was accounted for primarily by the 14 premenopausal women--the postmenopausal female and male depressive patients did not differ significantly from their respective controls. The average diurnal melatonin concentration also showed a trend toward being higher in both the female and male depressed patients. The melatonin measures were not consistently related to any of the previously reported hypothalamic-pituitary-adrenal cortical axis measures in these subjects. Our findings thus failed to confirm a "low melatonin syndrome" or an inverse relationship between nocturnal melatonin and nocturnal cortisol concentrations in depression. This discrepancy may be related to methodologic differences among studies; our data are in accord with those findings of the one other reported study in which normal controls were individually matched to patients on variables that were known to influence melatonin secretion. Most of the studies, including ours, have been cross-sectional.(ABSTRACT TRUNCATED AT 250 WORDS)

121 citations

Journal ArticleDOI
TL;DR: Oral melatonin supplementation in humans has a generally favourable safety profile with some exceptions, and most adverse effects can likely be easily avoided or managed by dosing in accordance with natural circadian rhythms.

82 citations

Journal ArticleDOI
TL;DR: The hypothesis that the pineal gland can exaggerate the development of CIA via a high release of melatonin, probably via enhancement of T-cell priming is supported.

77 citations

Journal ArticleDOI
TL;DR: Low levels of melatonin in semen were observed in infertile groups having reduced sperm motility, leucocytospermia, varicocele and NOA, suggesting that melatonin may be involved in the modulation of reproductive neuroendocrine axis in male infertility.
Abstract: Melatonin is a hormone produced by the pineal gland. There is much controversy about its relationship to the male reproductive process. In this study, seminal plasma as well as the serum melatonin levels were studied in different infertile male groups and were correlated with their semen parameters and hormonal levels. One hundred twenty male cases subdivided into six equal groups were consecutively included; fertile normozoospermic men, oligoasthenozoospermia (OA), OA with leucocytospermia, OA with varicocele, non-obstructive azoospermia (NOA) with high serum follicle stimulating hormone (FSH) and NOA with normal FSH. Semen analysis, estimation of melatonin, FSH, testosterone (T) and prolactin (PRL) hormone was carried out. Mean level of serum melatonin was higher than its corresponding seminal concentrations in all investigated groups with a positive correlation between their levels (r = 0.532, p = 0.01). Serum and seminal plasma melatonin levels in all infertile groups were reduced significantly compared with their levels in the fertile group. The lowest concentrations were in OA with leucocytospermia group. Melatonin in both serum and semen demonstrated significant correlation with sperm motility (r = 607, 0.623 respectively, p = 0.01). Serum melatonin correlated positively with serum PRL (r = 0.611, p = 0.01). It may be concluded that melatonin may be involved in the modulation of reproductive neuroendocrine axis in male infertility. Also, low levels of melatonin in semen were observed in infertile groups having reduced sperm motility, leucocytospermia, varicocele and NOA.

75 citations