Stimulation of ATP-driven Ca2+ pump in the basal-lateral plasma membranes of kidney cortex during compensatory renal growth.
During compensatory renal growth 45Ca2+ transport in basal-lateral plasma membrane vesicles isolated from the rat renal cortex have been investigated. Stimulation of Ca2(+)-ATPase activity was observed, without an effect of compensatory renal growth on Na+/Ca2+ exchanger activity and on passive Ca2+ permeability of the vesicles. Twelve hours following unilateral nephrectomy about 40% increase of Ca2(+)-ATPase activity above control value was observed and this effect was present until the end of the experimental period (7 days). When kinetic parameters for Ca2(+)-ATPase were studied in native membranes, an increase of Vmax was observed, whereas the Km for Ca2+ was similar in control vesicles and vesicles isolated from the remnant kidney. Depletion of endogenous calmodulin resulted in a decrease of Vmax and an increase of Km (Ca2+), while its addition reversed these parameters and increased the Hill coefficient from about 1 to about 2. Once again, only a significant increase of Vmax in vesicles isolated from the remnant kidney above the control value was observed. Finally, increase of Ca2(+)-ATPase activity during compensatory renal growth could be abolished by actinomycin D, indicating that its stimulation is due to protein synthesis.
Hadzić
A
A
Department of Physiology, Faculty of Medicine, University of Zagreb, Yugoslavia.
Sabolić
I
I
Banfić
H
H
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism / Q000494:pharmacology; D002352:Carrier Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D003609:Dactinomycin / Q000494:pharmacology; D005260:Female; D007668:Kidney / Q000254:growth & development* / Q000378:metabolism; D007700:Kinetics; D009392:Nephrectomy; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000494:pharmacology; D019831:Sodium-Calcium Exchanger
D015220:Calcium Channels; D002147:Calmodulin; D002352:Carrier Proteins; D019831:Sodium-Calcium Exchanger; D003609:Dactinomycin; D000001:Calcimycin; D000255:Adenosine Triphosphate; D012964:Sodium; D000252:Calcium-Transporting ATPases; D002118:Calcium