Serum stimulates the Na+,K+ pump in quiescent fibroblasts by increasing Na+ entry - PubMed (original) (raw)

Serum stimulates the Na+,K+ pump in quiescent fibroblasts by increasing Na+ entry

J B Smith et al. Proc Natl Acad Sci U S A. 1978 Nov.

Abstract

Two ionophores (monensin and gramicidin) that carry Na+ into 3T3 cells markedly enhance the rate of 86Rb+ uptake. Ouabain prevents both ionophores from increasing 86Rb+ uptake, indicating that the ionophores activate the Na+,K+ pump. Measurements of 86Rb+ uptake and cell Na+ and K+ over a range of monensin concentrations show that the activity of the Na+,K+ pump in 3T3 cells is limited by the supply of internal Na+ and is extremely sensitive to small changes in internal Na+. Serum rapidly enhances the rate of 22Na+ uptake and net Na+ entry when Na+ exit is inhibited by ouabain. At 0.3 microgram/ml, monensin increases the rate of net Na+ entry and activates the Na+,K+ pump by the same degree as serum. The stimulation of 86Rb+ uptake by serum or the ionophores has an absolute requirement for external Na+. Thus, serum appears to stimulate the Na+,K+ pump in quiescent 3T3 cells by increasing its supply of Na+.

PubMed Disclaimer

Similar articles

Cited by

References

    1. Proc Natl Acad Sci U S A. 1975 Nov;72(11):4492-5 - PubMed
    1. Exp Cell Res. 1977 Mar 15;105(2):223-36 - PubMed
    1. J Cell Physiol. 1975 Aug;86(1):59-70 - PubMed
    1. J Clin Invest. 1957 Jun;36(6 Part 1):816-24 - PubMed
    1. J Cell Biol. 1963 May;17:299-313 - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources