Vasopressin rapidly stimulates NA entry and NA-K pump activity in quiescent cultures of mouse 3T3 cells

✍ Scribed by Stanley A. Mendoza; Noel M. Wigglesworth; Enrique Rozengurt

• Publisher: John Wiley and Sons
• Year: 1980
• Tongue: English
• Weight: 773 KB
• Volume: 105
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1041050117

✦ Synopsis

Abstract

Addition of (Arg) vasopressin to quiescent cultures of Swiss 3T3 cells rapidly stimulates an ouabain‐sensitive ^86^Rb uptake. In contrast the hormone has no significant effect on the rate of efflux of this cation from preloaded cells. The stimulation of ^86^Rb uptake is cycloheximide‐insensitive, occurs within minutes of hormone addition and results from an increase in the Vmax of the uptake system. Vasopressin stimulates ion uptake in a concentration‐dependent fashion (1‐100 ng/ml); oxytocin also stimulated the Na‐K pump but at significantly higher concentrations. The stimulation of the Na‐K pump by vasopressin is apparently mediated by an increase in Na entry into the cells, since the hormone (1) strikingly shifts the concentration dependence on Na^+^ of the Na‐K pump, (2) increases ^22^Na uptake, and (3) increases intracellular Na contents when the efflux of this ion is blocked by ouabain. Since vasopressin is a potent mitogen for Swiss 3T3 cells, the results provide further evidence in support of a possible role of monovalent ion fluxes in signalling the initiation of growth stimulation.