Analysis of growth hormone release from rat anterior pituitary cells by reverse hemolytic plaque assay: influence of interleukin-1.
Interleukin-1 (IL-1) has been suggested to directly affect pituitary growth hormone (GH) release, although other investigators have failed to observe this effect. We examined the effects of IL-1 beta on GH secretion from single somatotrophs by means of reverse hemolytic plaque assay (RHPA). Anterior pituitary cells of adult male rats were enzymatically dispersed and subjected to RHPA. IL-1 beta at 100 pM and 1 nM, increased both the mean plaque area and the fraction of somatotrophs forming large plaques. IL-1 beta did not increase the mean plaque area in the presence of the IL-1 receptor antagonist (IL-1ra). IL-1 beta (1 nM) added together with GH-releasing hormone (GHRH; 10 nM), showed no additive effect on GHRH-induced GH release. The stimulatory action of IL-1 beta on the release of GH was suppressed by somatostatin. In conclusion, our data show that IL-1 beta stimulates GH-secretion through direct action on the pituitary.
Niimi
M
M
Department of Clinical Laboratory, Kagawa Medical School, Japan.
Sato
M
M
Wada
Y
Y
Tamaki
M
M
Takahara
J
J
Kawanishi
K
K
D000818:Animals; D002478:Cells, Cultured; D013006:Growth Hormone / Q000187:drug effects / Q000378:metabolism*; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology; D006462:Hemolytic Plaque Technique; D007375:Interleukin-1 / Q000494:pharmacology*; D008297:Male; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors; D013004:Somatostatin / Q000494:pharmacology
D007375:Interleukin-1; D017472:Receptors, Interleukin-1; D013004:Somatostatin; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone