AJP - Renal Physiology, Vol 259, Issue 5 752-F757, Copyright © 1990 by American Physiological Society
Polarity of kallikrein release and activation in perfused rat kidneys
M. P. Boric, J. Corthorn, R. Silva and J. S. Roblero
Departamento de Ciencias Fisiologicas, FCCBB, Pontificia Universidad Catolica de Chile, Santiago.
The polarity of release and activation of renal kallikrein and its
regulation by adrenal hormones was studied in isolated perfused rat
kidneys. Bilateral adrenalectomy (AX) produced a decrease in kallikrein and
prokallikrein excretion into urine and perfusate of isolated kidneys, as
well as in active kallikrein excretion in vivo. One-week treatment with
deoxycorticosterone acetate (DOCA 2.5 mg/day) or dexamethasone (DEX 0.25
mg/day) increased the urinary output of active and total kallikrein above
AX levels but below control. In contrast, neither corticoid increased
enzyme secretion to perfusate. Regardless of AX or corticosteroid
treatment, the prokallikrein fraction was 90% of total enzyme in perfusate
and only 40% in urine. These results confirm that adrenal steroids are
necessary for renal kallikrein synthesis and excretion; however, neither
DOCA nor DEX appears to be a unique regulator for release or activation of
this enzyme. In addition, whereas the processes of secretion and activation
toward the urine are regulated in parallel, kallikrein release to the
venous effluent seems to be regulated separately.
