AGE-RELATED-CHANGES IN G-PROTEINS OF THE KIDNEY MEDULLARY MEMBRANES IN THE CBA AND NEPHROGENIC DIABETES-INSIPIDUS (NDI) MICE

In the present study, the GTP-binding capacity and GTPase activity of G-proteins solubilized from kidney medulla membranes in young (10 day- old), adult (3-month) and NDI mice was measured. There was no differen ce between basic GTPase activity in adult CBA and NDI mice (56-6; 52-6 nmolP(i)/min/mg). In young animals it was low (1.4-0.15) (conc. of GT P, 2.5 mM). AVP (0.5 . 10(-6) M) increased the GTPase activity about 5 0% only in adult CBA mice. G-protein which is sensitive to cholera tox in was discovered by PAGE of the GTP-binding protein. It is supposed t hat there are different G-proteins in the kidney of immature, mature a nd NDI mice.