Effect of vasopressin and dehydration on protein-bound sulfhydryl and disulfide groups in renal cells

¹ Department of Pharmacology, State University of New York Upstate Medical Center, Syracuse, New York

Antidiuresis caused by the injection of vasopressin in rats can be correlated with a reduction in protein-bound sulfhydryl (PBSH) but not with changes in protein-bound disulfide (PBSS) in the cytoplasm of kidney tubular cells. During recovery from the effects of vasopressin PBSH increased while PBSS virtually disappeared. Amounts of vasopressin which were associated with a reduction in PBSH in the cytoplasm of renal cells produced a slight increase in liver cytoplasmic PBSH. Oxytocin did not produce these changes in PBSH in renal cells. Quantities of vasopressin as small as 0.1 milliunits given subcutaneously produced near maximal effects on PBSH. Dehydration produced effects similar to those observed with vasopressin injections and rehydration of dehydrated rats produced a recovery of PBSH and a temporary disappearance of PBSS. These results have been discussed and it is concluded that the PBSH changes observed cannot be produced by a stoichiometric binding with antidiuretic hormone. It is proposed that vasopressin, by reducing PBSH, produces some configurational changes in the membrane which might increase the permeability of these membranes to water and electrolytes.