Investigations on the acute effects of neuropeptides on the pituitary-adrenocortical function in normal and cold-stressed rats. I. Bombesin and neuromedin B.

摘要: The effects of a subcutaneous bolus injection 2 micrograms neurotensin (NT) or neuromedin N (NMN) on the function hypothalamo-pituitary-adrenocortical axis were investigated in both normal and cold-stressed rats. blood concentrations ACTH, corticosterone (B) aldosterone (ALDO) measured by specific radioimmunoassays 1, 4 h after neuropeptide administration. Cold stress enhanced plasma levels B ALDO, these rises lasted unchanged until h. NT did not affect either basal stress-stimulated ACTH B, while it lowered ALDO concentration at rats increased 1 stressed animals. NMN change level but markedly raise ALDO; other hand, strongly depressed response decreased h, without evoking apparent changes response. In light findings following conclusions hypotheses can be drawn suggested: (i) NMN, when administered relatively high dose, do release under conditions; (ii) NT, is able to prevent cold stress-induced stimulation secretion, probably inhibiting hypothalamic thermoregulatory centers; (iii) exert direct adrenocortical antisecretagogue secretagogue effects, respectively, which could explain evident lack correlation between circulating main adrenal steroid hormones