Calcitonin gene-related peptide as a GH secretagogue in human and rat pituitary somatotrophs.
To elucidate the role of calcitonin gene-related peptide (CGRP) in regulating pituitary function, we investigated the effects of CGRP and the related peptide adrenomedullin (AdM) on the secretion of growth hormone (GH) in vitro from human pituitary adenoma cells, rat pituitary tumor (GH3) cells, and normal rat pituitary cells. In 3 of 5 human somatotroph adenomas, GH secretion was stimulated by CGRP (1-100 nM). In one case of somatotroph adenoma, GH release was observed following the addition of 10 nM GHRH and 10 nM CGRP. The addition of CGRP or AdM (1 pM-10 nM) evoked GH secretion from GH3 cells with a bell-shaped distribution curve. CGRP (100 pM) caused the maximum increase of GH secretion (172+/-14 (mean+/-S.D.)% of control). The addition of CGRP8-37, an antagonist of CGRP type 1 receptors, inhibited the stimulatory effect of AdM but did not inhibit the effect of CGRP. The addition of CGRP and AdM evoked moderate GH secretion from normal rat pituitary cells. These results suggested that CGRP is a new GH secretagogue in human and rat pituitary tumor cells.
Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan.
Y
Y
Nakamura
A
A
Shimatsu
H
H
Murabe
H
H
Mizuta
C
C
Ihara
K
K
Nakao
D000236:Adenoma / Q000378:metabolism / Q000473:pathology; D053607:Adrenomedullin; D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology / Q000502:physiology*; D013006:Growth Hormone / Q000378:metabolism*; D019382:Human Growth Hormone / Q000378:metabolism*; D006801:Humans; D010455:Peptides / Q000494:pharmacology*; D010902:Pituitary Gland / Q000187:drug effects* / Q000378:metabolism; D010911:Pituitary Neoplasms / Q000378:metabolism / Q000473:pathology; D051381:Rats; D014407:Tumor Cells, Cultured
D010455:Peptides; D019382:Human Growth Hormone; D053607:Adrenomedullin; D013006:Growth Hormone; D015740:Calcitonin Gene-Related Peptide