ABSTRACT
Arginine vasotocin has long been known as an antidiuretic hormone in non-mammalian vertebrates. The peptide has also been found in mammalian tissues. The physiological significance of the peptide, however, has not yet been clarified in mammals. To define the effect of arginine vasotocin on the water and electrolyte balance in mammalian vertebrates, experiments have been done. Intrarenal arterial infusion of arginine vasotocin, 0.01-10ng/kg/min resulted in dose-dependent decreases in urine volume and free water clearance and an increase in urinary osmolarity. Arginine vasotocin, in a dose of 0.03ng/kg/min, induced an increase in water reabsorption without changes in glomerular filtration rate. Intrarenal infusion of arginine vasotocin in doses ranging from 0.1 to 3.0 or 10.0ng/kg/min resulted in decreases in glomerular filtration rate and renal plasma flow. However, no dose dependence were observed. Intrarenal infusion of arginine vasotocin from 0.3 to 10 ng/kg/min induced dose-dependent natriuretic and kaliuretic effects with concomitant suppression of renin secretion. The renal effects of arginine vasotocin were blocked by arginine vasopressin V2-receptor antagonist [d(CH2)5, D-Phe2, Ile4, Ala9-NH2]-vasopressin but were not blocked by[d(CH2)5, D-Ile2, Ile4, Arg8]- vaso pression. These data suggest that the effect of arginine vasotocin on the renal function are similar to that of vasopressin in mammalian vertebrates. The data also suggest that the renal effects of arginine vasotocin may be coupled to the receptor system which is similar, if not identical, to that of arginine vasopressin.