Early effects of uninephrectomy on k homeostasis in unanesthetized
rats.
Aizman, R. I., L. Rabinowitz, and C. Mayer-Harnisch.
Department of Human Physiology, University of California, Davis, CA
95616
APStracts 2:0266R, 1995.
Mechanisms underlying the change in K excretion (UKV) during the first
6 days following uninephrectomy (UNX) were examined in unanesthetized
rats. Arterial plasma K concentrations (PK) were 0.55 meq/l above
control values at 12 and 24 h after UNX but were not significantly
different 36-72 h after UNX. To determine if there was an increased
sensitivity of the distal K secretory mechanism to increases in PK,
an intragastric KCl infusion was given . The DUKV/DPK per kidney was
in the order: 6 day UNX > 2 day UNX > control. In the
normal rats an acute increase of 0.5 meq/l in PK increased UKV by an
amount approximating 25% of the increase in UKV observed 12-24 h
after UNX. Amiloride, administered 48 h after UNX, increased Na
excretion per kidney and decreased UKV per kidney approximately twice
as much in UNX as control groups. Thus an adaptive increase of
amiloride-inhibitable potassium secretion occurred within 2 days of
UNX and continued to increase thereafter. This potassium adaptation
may have been induced by transient increases in PK.
Received 15 February 1995; accepted in final form 13 September
1995.
APS Manuscript Number R121-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 31 October 95