[Effects of sleep on gonadotropin secretion]

Comparable to the period of adolescence in puberty, sleep exerts profound effects on the gonadotropin secretion in adult women. During the early follicular phase of the menstrual cycle, a slowing of the luteinising hormone (LH) pulse frequencies is concomitant with a rise in LH pulse amplitudes during sleep. A selective sleep-associated increase in opioidergic, but not in dopaminergic activity, may account for the decline in the LH pulse frequencies. Since pituitary gonadotropin responsiveness is virtually unchanged during sleep, the reasons for the enhanced LH pulse amplitudes remain unknown. Although the physiological meaning of this neuroendocrine manifestation is unexplained at present, the observed changes in the LH secretory profiles during sleep may represent close functional links between the endocrine secretion and the rest-activity cycle of the brain.