Neonatal glucocorticoid overexposure programs pituitary-adrenal function in ponies

作者：Jellyman J K^*; Valenzuela O A; Allen V L; Forhead A J; Holdstock N B; Fowden A L

来源：Domestic Animal Endocrinology, 2015, 50: 45-49.

DOI：10.1016/j.domaniend.2014.06.006

• Glucocorticoid
• Horse
• Pituitary
• Adrenal
• Hypoglycemia
• Cortisol
• ACTH

The present study tested the hypothesis that overexposure to endogenous glucocorticoids in neonatal life alters the reactivity of the hypothalamic-pituitary-adrenal (HPA) axis in ponies at 1 and 2 yr of age. Newborn foals received saline (0.9% NaCl, n = 8, control) or long-acting adrenocorticotropic hormone (ACTH(1-24)) (Depot Synacthen 0.125 mg intra-muscularly twice daily, n = 9) for 5 d after birth to raise cortisol concentrations 5- to 6-fold. At I and 2 yr of age, HPA axis function was assessed by bolus administration of short-acting ACTH(1-24) (1 mu g/kg intravenous) and insulin (0.5 U/kg intravenous) to induce hypoglycemic on separate days. Arterial blood samples were taken at 5 to 30-min intervals before and after drug administration to measure plasma ACTH and/or cortisol concentrations. There were no differences in the basal plasma ACTH or cortisol concentrations or in the cortisol response to exogenous ACTH(1-24) with neonatal treatment or age. At 1 and 2 yr of age, the increment in plasma ACTH but not cortisol at 60 min in response to insulin-induced hypoglycemia was greater in ponies treated neonatally with ACTH than saline (P < 0.05). Neonatal cortisol overexposure induced by neonatal ACTH treatment, therefore, alters functioning of the HPA axis in adult ponies.

• 出版日期2015-1