Receptor for peptide hormones involved in energy homeostasis, and method and compositions for use thereof

摘要

The invention relates to an energy homeostasis peptide hormone receptor, and in particular, a second common PACAP/VIP receptor (PACAP/VIP R-2 or R-2B) cDNA expressed in human adipocytes. Pituitary adenylate cyclase activating polypeptide (PACAP) and vasoactive intestinal polypeptide (VIP) are two structurally related peptides with multiple physiological effects. The present receptor recognizes PACAP-38 and VIP with similar affinity and is coupled to the cAMP-mediated signal transduction pathway. Transcripts of the second common PACAP/VIP R-2 receptor are also found in human brain and in a number of peripheral tissues, such as pancreas, muscle, heart, lung, kidney, stomach and at low levels in the liver, while transcripts of PACAP/VIP R-2B are not found in pancreas, stomach or kidney. Comparison of the tissue distribution of PACAP/VIP R-2 to that of the other two types of PACAP receptors (PACAP-Type 1 and the other common PACAP/VIP R-1) by RNase protection shows that each of the three PACAP receptors is expressed in a unique set of human peripheral tissues. However, PACAP/VIP R-2 is receptor with broadest distribution in human tissues. Thus, some of the physiological effects of PACAP-38 and VIP in peripheral tissues, especially in pancreas and skeletal muscle, could be mediated through the energy homeostasis peptide hormone receptor, and particularly the second common PACAP/VIP receptor.