title: Renin response to hemorrhage in conscious rats: effect of acute reductions in hematocrit.
abstract: This study examined the effect of prior exchange transfusion and acute reduction in hematocrit on the subsequent plasma renin concentration (PRC) response to 15 ml/kg hemorrhage in conscious cannulated rats. Long-Evans rats (400-500 g) were assigned to one of eight groups (6-8 rats/group). Rats were exchanged transfused (5 ml total) with whole blood, red blood cells and saline, plasma, or isotonic saline, with the two latter groups showing a decrease in hematocrit of 10-20%. Thirty minutes after exchange transfusion, rats were either subjected to a 0- (control) or 15-ml/kg hemorrhage. Control rats showed no change in mean arterial pressure or PRC regardless of exchange transfusion. The rats exchange transfused with saline had a significant decrease in arterial pH and a more profound hypotension after hemorrhage. PRC ranged from 7 +/- 1 to 11 +/- 1 ng.ml-1.h-1 after exchange transfusion. Subsequent hemorrhage resulted in an increase in PRC that was significantly greater in the saline-transfused group (45 +/- 16 ng.ml-1.h-1) 10 min after hemorrhage. We conclude that exchange transfusion with saline leads to an augmented renin response to hemorrhage in part due to a decrease in arterial pH and more severe hypotension.
authors.affiliation: Endocrine Research Laboratory, St. Luke's Medical Center, Milwaukee, Wisconsin 53215.
authors.forename: H
authors.initials: H
authors.lastname: Raff
mesh_terms: D000818:Animals; D001794:Blood Pressure; D005078:Exchange Transfusion, Whole Blood; D006400:Hematocrit; D006470:Hemorrhage / Q000097:blood*; D006863:Hydrogen-Ion Concentration; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012083:Renin / Q000097:blood*
chemical_list: D012083:Renin