Topographical localization of the receptors for luteinizing hormone-releasing hormone on the surface of dissociated pituitary cells.

Open Access
Publisher Website
Google Scholar
Abstract
A derivative of the hypothalamic peptide luteinizing hormone-releasing hormone (LHRH) was coupled to ferritin and the conjugate purified by gel chromatography. In its ability to stimulate the secretion of luteinizing hormone from [rat] pituitary cells in vitro, the conjugate has the same potency and specificity as the native peptide. When dissociated pituitary cells maintained in short-term culture are lightly fixed with formaldehyde and then incubated with the conjugate examination in the EM shows an even distribution of ferritin particles over the free cell surface of the gonadotropin cells. This binding appears to be specific for the LHRH receptor since it is prevented by a 10-fold excess of native peptide. In addition to the gonadotropin cells, some somatotropin and thyrotropin cells bind conjugate on their free surfaces under similar conditions. If living cells are incubated with the conjugate for 15 min, the bound conjugate becomes aggregated and then concentrated in 1 localized area of the cell surface. In this area, which lies immediately above the juxtanuclear Golgi complex, the plasma membrane is frequently invaginated in a manner which suggests that the bound, aggregated conjugate is internalized by endocytosis.

This publication has 18 references indexed in Scilit: