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Vertebrate reproduction is dependent on the operation of a central signal generator that directs the episodic release of gonadotropin-releasing hormone, a neuropeptide that stimulates secretion of the pituitary gonadotropic hormones and, thereby, controls gonadal function. The electrophysiological correlates of this pulse generator are characterized by(More)
Insulin-induced hypoglycemia (IIH) profoundly inhibits the activity of the hypothalamic GnRH pulse generator. The aim of this study was to determine the role of vasopressin and CRF in this response. Ovariectomized rhesus monkeys with chronically implanted recording electrodes in the mediobasal hypothalamus and with intracerebroventricular (icv) cannulas in(More)
In women and rhesus monkeys, both the negative and positive feedback actions of estradiol (E2) on gonadotropin secretion (inhibition followed by a surge) can be exerted directly at the level of the pituitary gland. We have tested the hypothesis that the positive feedback action of E2 represents but an "escape" from its negative feedback inhibition of(More)
The pulsatile secretion of luteinizing hormone (LH), occasioned by the pulsatile release of gonadotropin-releasing hormone (GnRH), is closely associated with concurrent increases in multiunit electrical activity in the mediobasal hypothalamus (MUA volleys), the electrophysiological correlates of GnRH pulse generator activity. These volleys represent a(More)
In mammals, gonadal function is controlled by a hypothalamic signal generator that directs the pulsatile release of gonadotropin-releasing hormone (GnRH) and the consequent pulsatile secretion of luteinizing hormone. In female rhesus monkeys, the electrophysiological correlates of GnRH pulse generator activity are abrupt, rhythmic increases in hypothalamic(More)
The relative roles of infant suckling and of maternal prolactin (PRL) secretion in lactational anovulation were studied in ovary-intact and ovariectomized rhesus monkeys nursing young that had been removed from their natural mothers. Hypothalamic gonadotropin-releasing hormone (GnRH) pulse generator activity was monitored electrophysiologically in freely(More)
Insulin-induced hypoglycemia causes somnolence in rhesus monkeys, a phenomenon usually considered an aspecific consequence of neuroglycopenia. Previous observations from our laboratory have raised the possibility that arginine vasopressin (AVP) may also play a role in this decrease in wakefulness. In the present study we tested this hypothesis by inducing(More)
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