Receptor-bound somatostatin and epidermal growth factor are processed differently in GH sub(4)C sub(1) rat pituitary cells

• Published in: The Journal of cell biology Vol. 102; no. 3; pp. 878 - 888
• Main Authors: Presky, D H, Schonbrunn, A
• Format: Journal Article
• Language: English
• Published: 01.01.1986
• Subjects: epidermal growth factor; pituitary; rats; somatostatin
• ISSN: 0021-9525

GH sub(4)C sub(1) cells, a clonal strain of rat pituitary tumor cells, have high-affinity, functional receptors for the inhibitory hypothalamic peptide somatostatin (SRIF) and for epidermal growth factor (EGF). In this study the authors examined the events that follow the initial binding of SRIF to its specific plasma membrane receptors in GH sub(4)C sub(1) cells and have compared the processing of receptor-bound SRIF with that of EGF. The results presented indicate that EGF underwent rapid receptor-mediated endocytosis in GH sub(4)C sub(1) cells and was subsequently degraded in lysosomes. In contrast, SRIF remained at the cell surface for several hours although it elicits its biological effects within minutes. After initial bindings of ( super(125)I-Tyr super(1))SRIF and super(125)I-EGF to their specific membrane receptors, these peptides are processed very differently in GH sub(4)C sub(1) cells.