Proliferation and intracellular pH in cultured proximal tubular cells.
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)
Larsson
S H
SH
Department of Pediatrics, Karolinska Institute, St. Göran's Children's Hospital, Stockholm, Sweden.
Fukuda
Y
Y
Kölare
S
S
Aperia
A
A
D000818:Animals; D001345:Autoradiography; D002352:Carrier Proteins / Q000378:metabolism; D002455:Cell Division; D002478:Cells, Cultured; D006863:Hydrogen-Ion Concentration; D007425:Intracellular Membranes / Q000378:metabolism*; D007687:Kidney Tubules, Proximal / Q000166:cytology* / Q000378:metabolism; D008938:Mitosis; D011522:Protons; D051381:Rats; D017923:Sodium-Hydrogen Exchangers; D013936:Thymidine
D002352:Carrier Proteins; D011522:Protons; D017923:Sodium-Hydrogen Exchangers; D013936:Thymidine