MOLECULAR-CLONING AND CHARACTERIZATION OF RAT V1B VASOPRESSIN RECEPTOR - EVIDENCE FOR ITS EXPRESSION IN EXTRA-PITUITARY TISSUES

Arginine vasopressin (AVP) modulates the secretion of ACTH through vasopressin receptor subtype V-lb in the pituitary. We recently cloned human V-lb, but several inconsistencies were found between the characteristics of this cloned receptor and those of rat pituitary membrane shown by previous workers. To clarify this issue, we report here the molecular cloning and functional expression of the cDNA encoding V-lb in rat pituitary. This receptor encodes425 amino acid protein having the highest identity with the human V-lb (81%). Expression of this receptor in COS-1 cells showed pharmacological characteristics of V-lb consistent with those of rat pituitary membrane. Northern blot and RT-PCR analyses revealed that mRNA of this receptor was expressed not only in anterior pituitary, but also in other tissues. This finding raises the possibility that V-lb may play a role in regulating cell functions of these tissues. (C) 1995 Academic Press, Inc.