The effect of agouti-related protein on growth hormone secretion in adult male rats.
Agouti-related protein (AGRP) and neuropeptide Y (NPY) are synthesized in the same neurons in the hypothalamic arcuate nucleus. We have previously shown that NPY/AGRP neurons contain growth hormone (GH) receptor mRNA, and are activated following systemic GH administration. We also reported that NPY inhibits GH secretion when administered centrally. In this study, we have examined the effect of AGRP on GH secretion. Central administration of AGRP (83-132) as a single injection of 1 or 10 microg/rat, or chronic treatment of 1 microg/rat, every 12 h for 7 days, did not alter the GH secretory pattern of adult male rats. AGRP (83-132) at doses of 1-100 nM (4 h) did not alter baseline- and GHRH-induced GH secretion from the rat pituitary cell cultures. These results suggest that AGRP does not play a significant role in the feedback regulation of the GH secretion.
Tamura
Hideki
H
Department of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-Ku, Tokyo 113-8603, Japan.
Kamegai
Jun
J
Shimizu
Takako
T
Ishii
Shinya
S
Sugihara
Hitoshi
H
Oikawa
Shinichi
S
D054369:Agouti-Related Protein; D000818:Animals; D005247:Feeding Behavior; D013006:Growth Hormone / Q000378:metabolism*; D013007:Growth Hormone-Releasing Hormone / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D009474:Neurons / Q000378:metabolism; D009478:Neuropeptide Y / Q000378:metabolism; D010902:Pituitary Gland / Q000166:cytology / Q000378:metabolism; D011506:Proteins / Q000378:metabolism / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D013997:Time Factors
C515197:AGRP protein, rat; D054369:Agouti-Related Protein; D036341:Intercellular Signaling Peptides and Proteins; D009478:Neuropeptide Y; D011506:Proteins; D012333:RNA, Messenger; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone