title: Pregnant rats with 5/6 nephrectomy have normal volume expansion despite lower renin and kallikrein.
abstract: To test the hypothesis that normal volume expansion during pregnancy is impaired during chronic renal failure, we evaluated the effects of 5/6 nephrectomy (Nx) in Sprague-Dawley rats. Partial Nx was produced by ligation of 2/3 renal arteries and contralateral Nx. Control rats had a sham operation. Four weeks later, rats were assigned to nonpregnant (n=6/each) or pregnant groups (n=11 to 12/each). At day 21, blood pressure, plasma volume, renal function, hormonal levels, and reproductive outcome were determined. Statistical analysis was performed by ANOVA, and values were expressed as mean+/-SEM. Rats with 5/6 Nx had proteinuria and lower creatinine clearance; pregnancy did not affect these parameters. Blood pressure increased in 5/6 Nx rats and was reduced by pregnancy. Both pregnant groups had lower hematocrit and higher plasma volume values (nonpregnant control, 13.4+/-0.2; nonpregnant 5/6 Nx, 14.4+/-0.2; pregnant control, 19.1+/-0.7, pregnant 5/6 Nx, 19+/-0.9 mL, P<0.001). Pregnancy increased plasma renin activity only in control rats (nonpregnant control, 2.0+/-0.7; nonpregnant 5/6 Nx, 1.6+/-1.1; pregnant control, 36.1+/-7.9, pregnant 5/6 Nx, 6.1+/-1.8 ng AI/mL per hour, P<0.001). Serum aldosterone levels were unaffected by 5/6 Nx and were higher in pregnant than in nonpregnant rats. Urinary kallikrein activity was reduced by 5/6 Nx and not changed by pregnancy (nonpregnant control, 1499+/-237; nonpregnant 5/6 Nx, 346+/-90; pregnant control, 1595+/-180, pregnant 5/6 Nx, 374+/-95 nmol/16 hours, P<0.001). No significant differences in fetal and placental weights were observed between control and 5/6 Nx rats. Present data indicate that 5/6 Nx pregnant rats were able to normally expand plasma volume despite lower renin and kallikrein levels.
authors.affiliation: Center for Medical Research, School of Medicine, Marcoleta 391, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile. ssalas@med.puc.cl
authors.forename: Sofía P
authors.initials: SP
authors.lastname: Salas
authors.forename: Andrea
authors.initials: A
authors.lastname: Giacaman
authors.forename: Carlos P
authors.initials: CP
authors.lastname: Vío
mesh_terms: D000818:Animals; D001794:Blood Pressure; D005260:Female; D007610:Kallikreins / Q000652:urine*; D007668:Kidney / Q000503:physiopathology; D007676:Kidney Failure, Chronic / Q000097:blood / Q000503:physiopathology* / Q000652:urine; D009392:Nephrectomy; D010953:Plasma Volume; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000503:physiopathology* / Q000652:urine; D051381:Rats; D017207:Rats, Sprague-Dawley; D012083:Renin / Q000097:blood*
chemical_list: D007610:Kallikreins; D012083:Renin