AJP - Renal Physiology, Vol 258, Issue 4 799-F804, Copyright © 1990 by American Physiological Society
Effects of amino acid isomers on canine renal hemodynamics
A. J. Premen and D. E. Dobbins
Department of Physiology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814-4799.
The major objective of this study was to ascertain whether the renal
hemodynamic response to amino acid infusion in dogs is stereospecific. To
test this hypothesis, we examined the renal hemodynamic effects of two
isomers (L and D) of an amino acid mixture of serine, alanine, and proline
(SAP; 0.051 mmol.kg-1.min-1) in anesthetized dogs. Intravenous infusion of
L-SAP (n = 6) significantly elevated renal blood flow (RBF) and glomerular
filtration rate (GFR) by 33 +/- 3 and 30 +/- 5%, respectively, over 1 h.
DL-SAP (n = 6) elevated RBF and GFR by only 14 +/- 3 and 13 +/- 3%,
respectively. Yet D-SAP (n = 6) failed to elevate either RBF or GFR over 1
h. Intravenous mannitol (940 mos-mol/kg; osmotic control; n = 6) also
failed to elevate renal hemodynamics. In six other dogs, intrarenal
infusion of L-, but not D-, SAP marginally elevated RBF and GFR by 13 +/- 2
and 12 +/- 2%, respectively, over 1 h. Infusion of alpha-aminoisobutyric
acid (0.051 mmol.kg-1.min-1; n = 6), an amino acid analogue that is
cotransported with sodium but not metabolized by renal cells, elevated RBF
and GFR by 22 +/- 5 and 18 +/- 6%, respectively, over 1 h. These data
indicate that vascular infusion of L, but not D, isomers of amino acids
elevate RBF and GFR. We therefore suggest the importance of amino acid
stereospecificity in the renal vascular response to amino acid infusion in
dogs.
