The in vitro effect of leptin on growth hormone secretion from primary cultured ovine somatotrophs

Abstract

Although existing data suggest an influence of leptin on circulating levels of growth hormone (GH), the action site and properties of leptin are still controversial. Using primary cultured ovine pituitary cells, we studied the direct effect of leptin on the secretion of GH. Pituitary cells were dissociated by collagenase and subjected to Percoll gradient centrifugation to enrich the somatotroph population to 60-80% of cells. Treatment of primary cultured ovine somatotrophs with leptin (10-9-10-7 M) for 30 min did not affect basal, GH-releasing hormone (GHRH) (10-7 M)- or GH-releasing peptide-2 (GHRP-2)(10-7 M)-stimulated GH secretion. Following treatment of cells for 1-3 d with leptin, GHRH-..