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Serum stimulates na entry and the Na‐K pump in quiescent cultures of epithelial cells (MDCK)
Author(s) -
Reznik Vivian M.,
Villela Javier,
Mendoza Stanley A.
Publication year - 1983
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041170212
Subject(s) - ouabain , intracellular , dna synthesis , stimulation , ion transporter , cell culture , chemistry , sodium , microbiology and biotechnology , biology , biophysics , dna , biochemistry , endocrinology , membrane , genetics , organic chemistry
The growth of an epithelial canine kidney line (MDCK) was reversibly arrested by gradually lowering the serum concentration in the medium over a 3‐day period. The cells were demonstrably quiescent by autoradiography after an additional 24 hours in serum‐free media. Addition of fresh serum produced DNA synthesis after an 18‐hour lag period. The quiescent cells then grew to confluency retaining their transport capacities as seen by the formation of “domes”. This system allows for measurement of monovalent ion fluxes and its relationship to growth regulation. The addition of fresh serum to quiescent MDCK cells increased the uptake of 86 Rb, a measure of Na‐K pump activity. This stimulation was mediated by increased uptake of Na into the cells. Serum‐stimulated DNA synthesis was blocked by the addition of ouabain in concentrations that inhibit the Na‐K pump. Serum appears to stimulate growth in epithelial cells by increasing the amount of intracellular Na available to the Na‐K pump. Monovalent ion transport may play a role in the regulation of epithelial cell proliferation.