AJP - Renal Physiology, Vol 258, Issue 3 697-F704, Copyright © 1990 by American Physiological Society
Proliferation and intracellular pH in cultured proximal tubular cells
S. H. Larsson, Y. Fukuda, S. Kolare and A. Aperia
Department of Pediatrics, Karolinska Institute, St. Goran's Children's Hospital, Stockholm, Sweden.
Renal proximal tubule (PT) cells from adult rats will maintain much of
their functional characteristics in short-term primary culture [S. Larsson,
A. Aperia, and C. Lechene. Am. J. Physiol. 251 (Cell Physiol. 20):
C455-C464, 1986]. This study examines the growth regulation of these highly
differentiated cells with particular reference to cell density,
intracellular pH (pHi), and the expression of the Na(+)-H+ exchanger. PT
cells were obtained from young adult rats and studied after 48 h in
culture. The mitotic rate was determined as the labeling index (LI) after
[3H]thymidine autoradiography, and pHi was determined by
2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein quantitative fluorescence
microscopy in single cells. Cells were grown either continuously in serum
(S) or were serum deprived after 24 h (D). The cells were nonconfluent and
grew in colonies. We defined the two peripheral layers of cells in a colony
as peripheral (P) cells and the remaining cells as central (C). In C cells
LI/h and pHi were in the range of what has been observed under in vivo
conditions. In S condition LI/h was 2.2 +/- 0.3% and in D condition was 0.3
+/- 0.1%. LI was significantly higher in P than in C cells both under S
(2.5 +/- 0.4-fold) and D conditions (5.6 +/- 0.8-fold). The rapidly growing
P cells had a significantly lower pHi than the growth-retarded C cells both
under S (7.25 +/- 0.02 vs. 7.30 +/- 0.01, P less than 0.05) and D
conditions (7.21 +/- 0.02 vs. 7.28 +/- 0.01, P less than 0.05).(ABSTRACT
TRUNCATED AT 250 WORDS)
