Peptide YY(3-36)-induced inhibition of food intake in female monkeys.

Peptide YY (PYY) is produced in L cells of the intestine and is released after eating. PYY circulates in a truncated form designated PYY(3-36). PYY(3-36) is thought to be a physiologic anorexigenic peptide.

Effect of leptin administration on ovulation in food-restricted rhesus monkeys.

A chronic negative energy balance due to low nutritional intake or increased energy expenditure alters several neuroendocrine axes. The reproductive and thyroid axes are inhibited while the adrenal axis is stimulated. In primates, anovulation resulting from a chronic negative energy balance is a condition often referred to as nutritional amenorrhea.

Developing a model of nutritional amenorrhea in rhesus monkeys.

Nutritional amenorrhea is defined as cessation of menstrual cycles resulting from a chronic negative energy balance. Although it is agreed that nutritional amenorrhea results from reduced secretion of GnRH, the neuroendocrine mechanisms leading to GnRH inhibition are poorly defined. Because the invasiveness of many neuroendocrine experimental approaches precludes its use in the clinical setting, we set out to establish a model of nutritional amenorrhea in rhesus monkeys.

Caloric restriction inhibits steroid-induced gonadotropin surges in ovariectomized rhesus monkeys.

We recently reported that caloric restriction inhibited ovulation in rhesus monkeys. The objective of the current study was to determine if caloric restriction affected the positive feedback response to ovarian steroids in non-human primates. Studies were conducted in four long-term ovariectomized rhesus monkeys.

Hypoglycemia does not affect gonadotroph responsiveness to gonadotropin-releasing hormone in rhesus monkeys.

Hypoglycemia inhibits gonadotropin secretion in primates by an undefined mechanism. Some evidence suggests that hypoglycemia inhibits gonadotropin secretion independent of gonadotropin-releasing hormone (GnRH) inhibition. To this end, the effect of insulininduced hypoglycemia on the luteinizing hormone (LH) and follicle-stimulating hormone (FSH) response to graded doses of GnRH (25, 75, and 250 ng/kg) administered at 120-min intervals was determined in rhesus monkeys.

Estrogen-induced gonadotropin surge in rhesus monkeys is not inhibited by cortisol synthesis inhibition or hypoglycemia.

Acute administration of corticotrophin-releasing hormone (CRH) has been shown to inhibit gonadotropin secretion in several species including rodents, sheep, humans, and nonhuman primates. Similarly, a variety of acute stressors have been shown to inhibit tonic gonadotropin secretion and may do so through a CRH mechanism. Stress-induced inhibition of tonic gonadotropin secretion below levels required for follicular maturation would be expected to inhibit ovulation.

Effectiveness of photodynamic ablation for destruction of endometrial explants in a rat endometriosis model.

Objective: To evaluate the potential of photodynamic therapy with aminolevulinic acid (ALA-PDT) for ablation of endometrial explants in a rat endometriosis model and to compare the effect of ALA-PDT, electrosurgery, and surgical resection on normal peritoneum.

Design: Prospective controlled experimental trial.

Setting: University medical center.