¹Department of Endocrinology, Hospital Ramón y Cajal, Madrid, Spain

Correspondence: Dr. R. García-Robles, Servicio de Endocrinologiía, Hospital Ramón y Cajal, Carretera de Colmenar Km 9,100, 28034 Madrid, Spain.

^*These data were presented in part at the Tenth Annual Scientific Meeting of The American Society of Hypertension, New York, May 1995. This study was supported by Research Project Grant 93/1, from Plan Nacional de Fomento a la Investigacion (BMS), Spain.

Received 19 July 1995; Revised  0000; Accepted 2 January 1996.

Abstract

The response of renal hemodynamics and sodium excretion (NaU) to an infusion of L-arginine, in the presence (experiment I) or absence (experiment II) of endogenous insulin secretion and during a sustained hyperinsulinemic euglycemic state (experiment III), was studied in 10 age-matched beagle dogs. The experiments were preceded by a standard oral glucose tolerance test (OGTT), performed 1 week before experiment I. One week resting periods were allowed between experiments I, II, and III.

No differences in renal hemodynamics and NaU were observed between basal (experiment I) and insulin secretion suppressed states (experiment II). L-Arginine infusion increased renal plasma flow (RPF), glomerular filtration rate (GFR), and NaU to a similar extent in both experiments. The hyperinsulinemic-euglycemic state (experiment III) induced a decrease in renal hemodynamics and NaU. In this situation, the infusion of L-arginine increased NaU, but was unable to increase RPF and GFR.

Our data suggest that a sustained hyperinsulinemic state can interact with the physiological vasoactive mechanisms involved in the regulation of renal vasculature. These results may be pertinent to human disease, especially in pathological conditions in which insulin resistance is present. Am J Hypertens 1996;9:681–686