Somatostatin receptor subtype 1 modulates basal inhibition of growth hormone release in somatotrophs

Somatostatin (SST) inhibits the secretion of many peptide hormones includin g growth hormone (GH). The various functions of SST are mediated through at least five different receptor subtypes (SSTR1-5), their precise physiologi cal roles have not been solved yet. Here we report on studies concerning th e functional role of SSTR1 in the modulation of GH release from somatotroph s. Primary cell cultures from pituitaries of wild-type SSTR1 mice exposed t o the SSTR1 selective somatostatin analog CH-275 show reduction of basal le vels of GH secretion whereas somatotrophs isolated from SSTR1 null mutant m ice did not respond to the agonist-mediated effect, This suggests that SSTR 1 is involved in modulating basal GH levels in primary pituitary cell cultu res and, together with SSTR2, may control the secretion of GH in the body. (C) 1999 Federation of European Biochemical Societies.