Molecular cloning and expression of a human anterior pituitary receptor for growth hormone-releasing hormone.
GH-releasing hormone (GHRH), acting through the GHRH receptor (GHRH-R), plays a pivotal role in the regulation of GH synthesis and secretion in the pituitary. It is possible that GHRH may serve other roles in other tissues. Here we report the cloning of a cDNA encoding a human GHRH-R from an acromegalic pituitary cDNA library. The isolated cDNA encodes a 423-amino acid protein that has seven putative transmembrane domains characteristic of G-protein-coupled receptors. It is a member of the secretin family of G-protein-coupled receptors and has 47%, 42%, 35%, and 28% identity with receptors for vasoactive intestinal peptide, secretin, calcitonin, and PTH, respectively. Transient expression of this cDNA in COS cells induced saturable, high affinity, GHRH-specific binding and also stimulated intracellular cAMP accumulation in response to physiological concentrations of GHRH. A specific GHRH antagonist blocked both binding and second messenger response. Northern analysis indicated that GHRH-R mRNA was most abundant in extracts of pituitary and was not detected in other tissues.
Gaylinn
B D
BD
Department of Medicine, University of Virginia School of Medicine, Charlottesville 22908.
Harrison
J K
JK
Zysk
J R
JR
Lyons
C E
CE
Lynch
K R
KR
Thorner
M O
MO
D000172:Acromegaly / Q000235:genetics / Q000378:metabolism; D000236:Adenoma / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D000242:Cyclic AMP / Q000378:metabolism; D004247:DNA / Q000235:genetics; D004273:DNA, Neoplasm / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D010911:Pituitary Neoplasms / Q000235:genetics; D012313:RNA / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D011956:Receptors, Cell Surface / Q000235:genetics; D018013:Receptors, Neuropeptide; D017981:Receptors, Neurotransmitter / Q000096:biosynthesis / Q000235:genetics*; D018017:Receptors, Pituitary Hormone-Regulating Hormone; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012756:Sheep; D015398:Signal Transduction
D004273:DNA, Neoplasm; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D018013:Receptors, Neuropeptide; D017981:Receptors, Neurotransmitter; D018017:Receptors, Pituitary Hormone-Regulating Hormone; D012313:RNA; D004247:DNA; D000242:Cyclic AMP; C048250:somatotropin releasing hormone receptor