Growth hormone-releasing factor stimulates proliferation of somatotrophs in vitro

摘要: The mitogenic effect of the hypothalamic peptides growth hormone-releasing factor (GRF) and somatostatin on cultured hormone (GH)-producing cells (somatotrophs) was studied. Using autoradiographic detection [3H]thymidine uptake immunocytochemical identification GH-producing cells, we show that 5 nM GRF causes a 20-fold increase in percentage somatotrophs labeled with [3H]thymidine. total number GRF-treated cultures increased by 60%. Somatostatin had no measurable labeling index itself, but it partly inhibited GRF-induced both cells. Forskolin caused an [3H]thymidine-labeled nucleus somatotroph similar to GRF. GH secretion as well cellular content GRF- or forskolin-treated culture time over entire period, whereas gradually decreased control somatostatin-treated during period. These data suggest regulate mitotic activity is possibly mediated cyclic AMP.