David C Bucholtz

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Restriction of glucose availability by 2-deoxyglucose (2DG) suppresses pulsatile LH release. The aim of the present study was to determine whether norepinephrine (NE) release in the paraventricular nucleus (PVN) is involved in the glucoprivic suppression of LH secretion in ovariectomized rats. Twelve days after ovariectomy, animals were stereotaxically(More)
Glucose availability controls reproductive activity through modulation of LH secretion. The aim of the present study was to determine whether the glucoprivic suppression is potentiated by gonadal steroids and if glucoprivic suppression of pulsatile LH release is sexually differentiated. Pulsatile LH secretion was examined in rats after peripheral (jugular)(More)
This study tested the hypothesis that central mechanisms regulating luteinizing hormone (LH) secretion are responsive to insulin. Our approach was to infuse insulin into the lateral ventricle of six streptozotocin-induced diabetic sheep in an amount that is normally present in the CSF when LH secretion is maintained by peripheral insulin administration. In(More)
The acute and long term effects of dietary restrictions on gonadotropin secretion were studied in ovariectomized female lambs. Nutritionally growth-restricted lambs which were chronically maintained at a body weight comparable to that at weaning (approximately 20 kg) became hypogonadotropic, exhibiting a low frequency of episodic LH discharges. Repeated(More)
The availability of metabolic fuels such as glucose is known to influence reproductive function. Peripheral administration of 2-deoxyglucose (2DG), a competitive inhibitor of glycolysis, inhibits pulsatile LH secretion in the rat and growth-retarded lamb. We hypothesized that such glucoprivic suppression of LH secretion is mediated by the lower brain stem,(More)
To test the hypothesis that mechanisms controlling the secretion of LH are modulated by glucose availability, the acute effects of glucoprivation were studied. The model was the gonadectomized male lamb raised on a limited diet of artificial milk. The approach was to monitor LH secretion before and after the administration of a competitive antagonist of(More)
Changes in glucose availability are proposed to modulate pulsatile GnRH secretion, and at least two anatomical sites, the liver and hindbrain, may serve as glucose sensors. The present study determined the relative importance of these putative glucose-sensing areas in regulating pulsatile LH secretion in the sheep. Our approach was to administer the(More)
Puberty in the female lamb is accompanied by an increased frequency of LH pulses, and during normal development this is preceded by a decline in GH. Conversely, in the growth-retarded lamb, when LH levels are depressed by low nutrition, GH secretion is elevated. Based upon this inverse relationship, we tested the hypothesis that GH may act as a metabolic(More)
Glutamate and aspartate have been hypothesized to function as neurotransmitters in the regulation of the gonadotropin-releasing hormone (GnRH) neurosecretory system. We, therefore, determined if hypothalamic stimulation of luteinizing hormone (LH) secretion in the intact prepubertal female lamb could be achieved by intravenous injection of(More)
This study tested the hypothesis that LH secretion is modulated by insulin and that the responsiveness to hypoinsulinemia is enhanced by sex steroids. The model was the developing male lamb (12-26 wk of age) rendered diabetic by chemically induced necrosis of insulin-secreting tissue (streptozotocin). Our approach was to monitor LH secretion under diabetic(More)