Effects of secretin on renal functions in the dogs

Publisher Website
Google Scholar
Abstract
In anesthetized mongrel dogs, the intrarenal arterial (0.2 .apprx. 1.0 unit/kg .cntdot. min) and the i.v. infusion (0.4 .apprx. 2.0 unit/kg .cntdot. min) of secretin caused dose-dependent increases of RBF [renal blood flow], accompanied by decreases of the calculated afferent arteriolar resistance (Ra) and efferent arteriolar resistance (Re), but produced no significant effect on GFR [glomerular filtration rate], urine flow, electrolyte excretion, osmolar clearance and free water reabsorption. The distribution of cortical blood flow was examined using the radioactive microsphere technique. The intrarenal infusion of secretion (1.0 unit/kg .cntdot. min) increased renal cortical blood flow in the juxtamedullary area much more than in the superficial area, shifting the blood flow from the outer to the inner zone. Simultaneous intrarenal infusion of secretin (1.0 unit/kg .cntdot. min) and glucagon (0.5 .mu.g/kg .cntdot. min) produced increases in GFR, urine flow and electrolyte excretion to a lesser degree than those induced by glucagon alone, whereas the increment in RBF and the decreases in Ra and Re were almost to the same degree as those caused by secretin alone. Secretin produces the dilation of afferent and efferent arterioles, resulting in an increase in RBF, with no change in GFR and urine flow. The effects of glucagon on renal functions are masked by secretin mainly through the effects on renal hemodynamics.