[Antidiuretic hormone content in the neurohypophysis of adult white rats after hydrocortisone administration in the early postnatal period].

The age-related time-course of changes in arginine-vasopressin (AVP) content in the pituitary gland was studied in adult intact Wistar rats. In 60-day-old rats, the hormone content was measured before and after 24 h of water deprivation. In adult rats treated with a single injection of hydrocortisone at different times after birth, the content of AVP remained high in rats injected with hydrocortisone on day 2 or day 5 after birth, exceeding significantly the content of AVP in intact rats. The animals injected with hydrocortisone on day 9 or 15 manifested a more noticeable reduction in the hormone content, as was the case in intact rats. It is suggested that the first five days after birth is a critical period in the formation of the central regulation of AVP secretion with high sensitivity to short-term changes in corticosteroid balance.