Effects of arginine-8-vasopressin and 1-deamino-8-D-arginine-vasopressin on ACTH secretion in rats

: The corticotropin-releasing effect of arginine-8-vasopressin (AVP) has been compared to that of 1-deamino-8-D-arginine-vasopressin (dDAVP) in male rats of R-Amsterdam strain. AVP increased the level of ACTH and corticosterone in the peripheral blood in a dose-dependent manner. In contrast to AVP, a very potent antidiuretic agent dDAVP which is devoid of pressor activity had no effect on ACTH release and did not stimulate the secretion of corticosterone. It is concluded that CRF activity of vasopressin in vivo is related to its pressor activity. These data are in agreement with the previous findings of these authors demonstrating that dDAVP shows a very low affinity for vasopressin receptors of the cell membranes in the adenohypophysis.