Picrotoxinin and Phorbol-12-Myristate-13-Acetate Stimulate the Secretion of Multiple Forms of Somatostatin from Cultured Rat Brain Cells

The molecular forms of somatostatin (SRIF) secreted by cultured fetal rat brain cells were resolved using reverse phase high performance liquid chromatography followed by radioimmunoassay. Multiple forms of SRIF-like immunoactivity were detected in media from cells treated with either picrotoxinin, phorbol-12-myristate-13-acetate, or high potassium. For stimulated cells, elevated levels of an SRIF-28-like molecule, an SRIF-14-like molecule, and a hydrophobic SRIF-like molecule were observed compared to basal conditions. All three forms of SRIF-like molecules were also detected in acid extracts of whole cells. The data are consistent with the possibility that secretion of multiple SRIFs , including SRIF-28, may be regulated by multiple effectors and mechanisms.