Glucocorticoid Hormones Increase the Activity of Plasma Membrane Alkaline Phosphodiesterase I in Rat Hepatoma Cells

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 77; no. 2; pp. 1005 - 1009
• Main Authors: Rousseau, Guy G., Amar-Costesec, Alain, Verhaegen, Martine, Granner, Daryl K.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 01.02.1980; National Acad Sciences
• Subjects: Adipocytes; Animals; Cell adhesion; Cell Membrane - enzymology; Cell membranes; Cells; Cells, Cultured; Dexamethasone - antagonists & inhibitors; Dexamethasone - pharmacology; Enzyme Induction - drug effects; Enzymes; Glucocorticoids; Glucocorticoids - pharmacology; Hepatocytes; Hormones; Hydrocortisone - pharmacology; Kinetics; Liver Neoplasms, Experimental - enzymology; Lymphocytes; Nucleotidases - metabolism; Phosphodiesterase I; Phosphoric Diester Hydrolases - biosynthesis; Rats; Steroids; Time Factors; Tyrosine Transaminase - metabolism
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.77.2.1005

In rat hepatoma cells the synthetic glucocorticoid dexamethasone causes a 3-fold increase in the activity of the plasma membrane enzyme alkaline phosphodiesterase I (oligonucleate 5′-nucleotidohydrolase, EC 3.1.4.1). The data are consistent with an induction phenomenon mediated by the glucocorticoid receptor involved in tyrosine aminotransferase induction. The effect on alkaline phosphodiesterase I is not a reflection of a general membrane effect of dexamethasone, because the activity of three other enzymes of the plasma membrane is unaffected. On the other hand, nucleoside diphosphatase (nucleoside diphosphate phosphohydrolase acting on ADP) activity is inhibited. Thus, two more enzymes sensitive to glucocorticoids have been identified in a cell line in which these hormones influence only very few gene products. This paper describes enzymatic changes in the plasma membrane of rat hepatoma cells in which glucocorticoids normalize a number of membrane-associated processes that are considered to be characteristic of transformed cells.