Integrative effects of egf on metabolism and proliferation in
primary cultures of renal proximal tubule cells.
Nowak, Grayna, and Rick G. Schnellmann.
University of Arkansas for Medical Sciences, Department of
Pharmacology and Toxicology, 4301 West Markham St., Little Rock, AR
72205-7199
APStracts 2:0204C, 1995.
This study examined the relationship between alterations in cellular
metabolism and induction of proliferation in renal proximal tubule
cells (RPTC) after EGF exposure. EGF treatment (10 ng/ml) of
confluent RPTC cultures for 6 consecutive days increased monolayer
DNA content 3.3-fold. EGF-stimulated proliferation of RPTC was
preceded by a rapid (within 4 hours) induction of glycolysis and a
decrease in basal and ouabain-sensitive oxygen consumption (20% and
30%, respectively). EGF stimulated the pentose cycle by 58% and
decreased gluconeogenesis by 48%. Supplementation of the culture
medium with ribose-5-phosphate or ribose abolished the stimulation of
glycolysis and the pentose cycle by EGF but had no effect on
proliferation. These results show that EGF rapidly stimulates the
pentose cycle, shifts glucose metabolism from gluconeogenesis to
glycolysis, and decreases oxygen consumption prior to any increase in
proliferation. The lack of an EGF effect on the pentose cycle and
glycolysis in the presence of exogenous precursors for DNA synthesis
suggests that the stimulation of these pathways prior to
proliferation is due to increased demands for ribose for subsequent
nucleic acid synthesis.
Received 21 November 1994; accepted in final form 19 May 1995.
APS Manuscript Number C678-4.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 26 May 1995.