RENAL HANDLING OF SODIUM AFTER AN ORAL PROTEIN LOAD IN ADULT HUMANS

This investigation was designed to study (1) renal sodium handling after an oral protein load and (2) its relationship to some known determinants of the hemodynamic response (glucagon, insulin, growth hormone, renin, aldosterone, and plasma amino acid concentration). To this end of group of 8 adult subjects was studied before (three 30-min clearances) and after a meat meal (MM; five 30-min clearances at 30, 60, 90, 120 and 180 min). The MM provided 2 g/kg BW of protein. Within 30 min from the MM an hyperfiltration response was seen, which was paralleled by a 2-fold increase in plasma alanine concentration while total plasma amino acid concentration was not different from the baseline values. The hemodynamic response was associated with a normally operating tubuloglomerular feedback mechanism independent of renin-aldosterone activity, but possibly associated with an early increase in plasma glucagon concentration and later on with a modest increase in postmeal plasma insuling concentration.