SYSTEMIC FACTORS AND RENAL HEMODYNAMIC-EFFECTS OF HIGH-PROTEIN MEAL VERSUS LOW-PROTEIN MEAL IN CONSCIOUS DOGS

The effects of a high-protein (HP) and low-protein (LP) meal on glomer ular filtration rate (GFR), effective renal plasma flow (ERPF), and re nal vascular resistance (RVR) were examined in conscious dogs. Ingesti on of the HP and LP meal produced a temporary increase in systemic hem odynamic parameters due in part to a 'cephalic phase' of sympathetic e xcitement. However only the HP significantly altered renal hemodynamic s, i.e. GFR, ERPF and RVR. Plasma renin activity (PRA), serum aldoster one and plasma atrial natriuretic peptide (ANP) concentrations were no t significantly altered by either a HP or LP meal. Of all the serum el ectrolytes measured, serum Ca2+ concentrations were significantly lowe r after a HP meal. It would appear that protein-meal-induced changes i n renal hemodynamics are independent of changes in systemic hemodynami cs. The exact mechanism of action of a HP meal on renal hemodynamics i s not clear, but it appears that one mechanism by which a HP meal may alter renal hemodynamics is by altered calcium homeostasis.