Angiotensin II effects upon the glomerular microcirculation and ultrafiltration coefficient of the rat.
Open Access
- 1 February 1976
- journal article
- Published by American Society for Clinical Investigation in Journal of Clinical Investigation
- Vol. 57 (2) , 419-434
- https://doi.org/10.1172/jci108293
Abstract
The effects of both synthetic and biologically produced angiotensin II (AII) upon the process of glolerular filtration were examined in the plasma-expanded (2.5% body wt) Munich-Wistar rat, by micropuncture evaluation of pressures, nephron plasma flow (rpf) and filtration rate (sngfr). Plasma expansion was chosen as a control condition because (a) response to AII was uniform and predictable, (b) endogenous generation of AII was presumably suppressed, and (c) the high control values for rpf permitted accurate determination of values for the glomerular permeability coefficient (LpA) before and during AII infusion. With subpressor quantities of synthetic Asn-1, Val-5 AII (less than 5 ng/100 g body wt/min), sngfr fell from 47.7 in the control group to 39.8 nl/min/g kidney (P less than 0.005). The rpf fell to 60% of control values (P less than 0.001). Measurement of glomerular capillary (PG) and Bowman's space (Pt) hydrostatic pressures in surface glomeruli with a servo-nulling device permitted evaluation of the hydrostatic pressure gradient (deltaP = PG - Pi). DeltaP increased from 38.1 +/- 1.2 in control to 45.9 +/- 1.3 mm Hg after Asn-1, Val-5 AII and essentially neutralized the effect of decreased rpf in sngfr. The sngfr then fell as a result of a decreased in LpA from 0.063 +/- 0.008 in control to 0.028 +/- 0.004 nl/s/g kidney/mm Hg after Asn-1, Val-5 AII (P less than 0.02). Lower doses of Asp-1, Ile-5 AII (less than 3 ng/100 g body wt/min) had no effect on sngfr, rpf, deltaP, and afferent and efferent vascular resistance, but significantly elevated systemic blood pressure, suggesting peripheral effects on smooth muscle at this low dose. LpA was 0.044 +/- 0.007 nl/s/g kidney/mm Hg after low-dose Asp-1, Ile-5 AII, and 0.063 +/- 0.008 in the control group (0.02 greater than P greater than 0.1). Higher, equally pressor doses of native AII (5 ng/100 g body wt/min) produced effects almost identical to similar quantites of synthetic Asn-1, Val-5 AII upon rpf, deltaP, sngfr, and renal vascular resistance. LpA again fell to 0.026 +/- 0.004 nl/s/g kidney/mn Hg, a value almost identical to that after the synthetic AII. Paired studies with Asp-1, Ile-5 AII also demonstrated a consistent reduction in LpA.Keywords
This publication has 37 references indexed in Scilit:
- Glomerular filtration response to elevated ureteral pressure in both the hydropenic and the plasma-expanded rat.Circulation Research, 1975
- The mechanism of acute renal failure after uranyl nitrate.Journal of Clinical Investigation, 1975
- Comparative Effects of Angiotensin and ACTH on Cyclic AMP and Steroidogenesis in Isolated Bovine Adrenal CellsJournal of Clinical Investigation, 1973
- Comparative Studies on Angiotensins. II. Structure of Rat Angiotensin and Its Identification by DNS-MethodCHEMICAL & PHARMACEUTICAL BULLETIN, 1972
- Effects of Angiotensin Infusion on the Isolated Rabbit KidneyExperimental Biology and Medicine, 1971
- Site of Action of Angiotensin and other Vasoconstrictors on the KidneyCanadian Journal of Physiology and Pharmacology, 1971
- Angiotensin II in arterial and renal venous plasma and renal lymph in the dogJournal of Clinical Investigation, 1971
- RENIN AND RENAL AUTOREGULATIONThe Lancet, 1968
- Tissue Hormones: Angiotensin, Bradykinin and the Regulation of Regional Blood FlowsMedical Clinics of North America, 1968
- Effect of angiotensin and beta-adrenergic stimulation on venous smooth muscleAmerican Heart Journal, 1966