Vasopressin and A1 noradrenaline turnover during food or water deprivationin the rat

In the present study, we have examined in Wistar rats the effects of food o r water deprivation of 3 days on the hypophyso-adrenal axis, vasopressinerg ic system and activity of Al noradrenergic brain stem cell group, which is involved in the control of the hypothalamic neuro-endocrine activity. Level s of adrenocorticotropic hormone (ACTH) and vasopressin (AVP) were determin ed by radio-immunoassay, and corticosterone level was determined by fluorim etric method. Plasma levels of ACTH and corticosterone were greatly increas ed in both groups of rats. In water-deprived rats: plasma AVP (13.83 +/- 1. 63 vs. 3.03 +/- 0.23 pg/ml) and osmolality levels were significantly elevat ed with a marked decrease of AVP hypophysis content (272 +/- 65 vs. 1098 +/ - 75 ng/mg protein), but not in food-deprived rats in which osmolality did not change and AVP remained stocked (2082 +/- 216 ng/mg protein) in the hyp ophysis without release in the plasma (1.11+/-0.23 pg/ml). These observatio ns indicated that both food-deprivation and water-deprivation stimulated th e pituitary-adrenal axis thereby suggesting a stress state. AVP production is stimulated both by fluid and food restriction but is secreted with diffe rential effects: during food restriction AVP secretion is limited to suppor ting the hypothalamic-pituitary-adrenal system. (C) 2000 Elsevier Science I nc. All rights reserved.