AJP - Regulatory, Integrative and Comparative Physiology, Vol 257, Issue 6 1467-R1473, Copyright © 1989 by American Physiological Society
Increased urinary clearance of lysine vasopressin in the deoxycorticosterone acetate-hypertensive pig
W. D. Ling, D. P. Brooks, J. T. Crofton, L. Share and D. F. Bohr
Department of Physiology, University of Tennessee, Memphis 38263.
We have previously reported an increased urinary excretion of vasopressin
without a rise in circulating levels of this hormone in the
deoxycorticosterone acetate (DOCA)-hypertensive pig (DH). The present study
was designed to characterize the renal handling of vasopressin in DH that
might account for this paradox. DOCA hypertension was produced in seven
domestic female pigs by means of subcutaneous implants of Silastic rubber
impregnated with DOCA. Thirty days after DOCA implantation, urinary
clearances of inulin, para-aminohippurate (PAH), and vasopressin were
measured in the conscious animals during infusion of a 5% dextrose
solution, first without and then with lysine vasopressin. Subsequent to
this study, four of the pigs were placed on a low-sodium (10 meq/kg food)
diet for 4 wk. At the end of this period, the clearances were again
evaluated. We observed an increased urinary vasopressin clearance (CLVP) in
the DH associated with an increased urinary flow but without significant
changes in the clearances of inulin or PAH. Dietary sodium restrictions
reversed the hypertension and the increased urinary flow and returned the
CLVP to normotensive levels. These results indicate that the increased
urinary excretion of vasopressin in DH is because of an increased urinary
clearance of this hormone. This increased urinary CLVP is the consequence
of the high urine flow in these pigs.
