Circadian profiles of progesterone, gonadotropins, cortisol and corticotropin in cycling and postmenopausal women.

Little is known about the regulation of temporal variations of progesterone over the 24-hr span in young cycling women as well as in postmenopausal women. The purpose of the present study was to investigate the relationships between diurnal variations of progesterone and diurnal variations of hormones of the gonadotropic and corticotropic axes, and to provide further information on the source of progesterone secretion under physiological conditions. Twenty-four-hour hormonal profiles were explored under well-controlled laboratory conditions in 10 healthy women (21-36 yr old) with normal ovulatory cycles during early-mid follicular and late luteal phases, and in 8 healthy postmenopausal women (48-74 yr old).

The important role of sleep in metabolism.

Both reduction in total sleep duration with slow-wave sleep (SWS) largely preserved and alterations of sleep quality (especially marked reduction of SWS) with preservation of total sleep duration are associated with insulin resistance without compensatory increase in insulin secretion, resulting in impaired glucose tolerance and increased risk of type 2 diabetes. When performed under rigorously controlled conditions of energy intake and physical activity, sleep restriction is also associated with a decrease in circulating levels of leptin (an anorexigenic hormone) and an increase in circulating levels of ghrelin (an orexigenic hormone), hunger and appetite. Furthermore, sleep restriction is also associated with a stimulation of brain regions sensitive to food stimuli, indicating that sleep loss may lead to obesity through the selection of high-calorie food.

Sleep and hormonal changes in aging.

Age-related sleep and endocrinometabolic alterations frequently interact with each other. For many hormones, sleep curtailment in young healthy subjects results in alterations strikingly similar to those observed in healthy old subjects not submitted to sleep restriction. Thus, recurrent sleep restriction, which is currently experienced by a substantial and rapidly growing proportion of children and young adults, might contribute to accelerate the senescence of endocrine and metabolic function.

Effects of a 3-week dehydroepiandrosterone administration on sleep, sex steroids and multiple 24-h hormonal profiles in postmenopausal women: a pilot study.

Objective: Dehydroepiandrosterone (DHEA) administration is widely evocated as a 'fountain of youth', but previous studies have provided inconsistent results. We aimed to investigate in healthy postmenopausal women the effects of a 3-week oral DHEA administration on individual steroid levels, multiple 24-h hormonal profiles and sleep architecture.

Design: Seven healthy nonobese postmenopausal women, off hormone replacement therapy for ≥2 months, were investigated in a randomized, crossover, double-blind, placebo-controlled study.

Progesterone prevents sleep disturbances and modulates GH, TSH, and melatonin secretion in postmenopausal women.

Context: A number of neuroactive progesterone metabolites produce sedative-like effects. However, the effects of progesterone administration on sleep are not well characterized.

Objective: To investigate the effects of a 3-wk progesterone administration on sleep architecture and multiple hormonal profiles.

A potential role of endogenous progesterone in modulation of GH, prolactin and thyrotrophin secretion during normal menstrual cycle.

Objective: Previous studies investigating the fluctuations of endocrine secretion across the menstrual cycle yielded inconsistent results. Our objective was to evaluate during the menstrual cycle the potential role of endogenous oestradiol and progesterone in the regulation of hormones primarily controlled by the circadian clock and/or the sleep-wake cycle.

Subjects And Design: Ten normally cycling young lean women were investigated once during follicular and once during luteal phase.

Sex hormone binding globulin decrease as a potential pathogenetic factor for hirsutism in adolescent girls.

We investigated 252 non-obese female subjects aged 13-39 years to evaluate if an exaggerated descent of sex hormone binding globulin (SHBG) levels during adolescence can play a role in the development of hirsutism. Body hair was assessed according to Ferriman and Gallwey (FG), with a stringent criterion of normality of < or = 4. In 13-14 years girls, SHBG and free testosterone (FT) levels were similar in "hirsute" girls (FG > 4) and controls (FG < or = 4, regular menstrual cycles, no acne).

Metabolic and endocrine effects of sleep deprivation.

Sleep deprivation has multiple effects on endocrine and metabolic function. In particular, sleep restriction is accompanied by increased cortisol levels in the afternoon and early evening and a shorter quiescent period compared with extended sleep periods. Those alterations could facilitate central and peripheral disturbances that are associated with glucocorticoid excess, such as memory deficits, and are similar to those observed in aging.

Sex differences in nocturnal growth hormone and prolactin secretion in healthy older adults: relationships with sleep EEG variables.

Study Objectives: To examine sex differences in nocturnal growth hormone and prolactin release in older adults.

Design: Sleep was polygraphically recorded for 2 consecutive nights, and blood was sampled at frequent intervals during the last 24 hours.

Setting: The University of Chicago Clinical Research Center.

Phase-shifts of 24-h rhythms of hormonal release and body temperature following early evening administration of the melatonin agonist agomelatine in healthy older men.

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.

Leptin levels are dependent on sleep duration: relationships with sympathovagal balance, carbohydrate regulation, cortisol, and thyrotropin.

Sleep plays an important role in energy homeostasis. The present study tests the hypothesis that circulating levels of leptin, a hormone that signals energy balance to the brain, are influenced by sleep duration. We also analyzed associations between leptin and sympathovagal balance, cortisol, TSH, glucose, and insulin under different bedtime conditions.

Reciprocal interactions between the GH axis and sleep.

For more than 30 years, growth hormone (GH) has been observed to be preferentially secreted during deep, slow-wave sleep (SWS). However, the mechanisms that underlie this robust relationship that links anabolic processes in the body with behavioral rest and decreased cerebral metabolism remain to be elucidated. Current evidence indicates that GH secretion during the beginning of sleep appears to be primarily regulated by GH-releasing hormone (GHRH) stimulation occurring during a period of relative somatostatin withdrawal, which also is associated with elevated levels of circulating ghrelin.

Immediate effects of an 8-h advance shift of the rest-activity cycle on 24-h profiles of cortisol.

To investigate the adaptation of plasma cortisol profiles to an abrupt phase advance of the rest-activity cycle, eight normal young subjects were submitted in a sleep laboratory to an 8-h advance shift of their sleep-wake and dark-light cycles. The shift was achieved by advancing bedtimes from 2300-0700 to 1500-2300. Blood samples were obtained at 20-min intervals for 68 consecutive hours.