Studies of the regulation of the hypothalamic-pituitary-adrenal axis in sheep with hypothalamic-pituitary disconnection i. Effect of an audiovisual stimulus and insulin-induced hypoglycemia

Abstract

These studies were undertaken to characterize the secretion of adrenocorticotropin (ACTH), immunoreactive (ir)β-endorphin (ir-β-EP) and ir α-melanocyte-stimulating hormone (ir-α-MSH) from the surgically isolated ovine pituitary in response to an audiovisual stress (barking dog, 3 min) and insulin hypoglycemia. The studies were performed in 4 ovariectomized. Hypothalamo-pituitary-disconnected (HPD) and 4 sham-HPD ewes bearing indwelling jugular venous catheters. Basal concentrations of the three pro-opiomelanocortin (POMC) peptides and plasma cortisol were significantly increased in the HPD animals. When the control ewes were exposed to the audiovisual stimulus, plasma ACTH. ir-β-EP and ir-α-..