GRF increases release of growth hormone and arachidonate from anterior pituitary cells.
Arachidonate and its metabolites increase growth hormone release in vitro. A study was designed to determine whether arachidonate release from anterior pituitary cells is modified by growth hormone-releasing factor (GRF) or somatostatin (SRIF). Cultured pituitary cells were incubated with [3H]arachidonate to esterify the long-chain fatty acid into cellular lipids. The cells were extensively washed with medium containing no [3H]arachidonate and then incubated with GRF and/or SRIF for 30 min. The incubation medium was then extracted with ethyl acetate, and following thin-layer chromatographic separation, the radioactivity in the [3H]arachidonate band was measured. GRF in a concentration-dependent manner (1-30 nM) stimulated growth hormone and arachidonate release, whereas SRIF (100 nM) blocked the GRF-induced increase of growth hormone and arachidonate release. The effects of GRF on growth hormone and arachidonate were evident at time intervals as brief as 5 min. These findings support the hypothesis that arachidonate may play a role in the GRF-induced growth hormone release.
Judd
A M
AM
Koike
K
K
MacLeod
R M
RM
D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism*; D002478:Cells, Cultured; D002855:Chromatography, Thin Layer; D003470:Culture Media; D013006:Growth Hormone / Q000378:metabolism*; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology*; D008297:Male; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000494:pharmacology*; D013997:Time Factors
D001095:Arachidonic Acids; D003470:Culture Media; D016718:Arachidonic Acid; D013004:Somatostatin; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone