Effects of Chronic and Acute Protein Administration on Renal Function in Patients with Chronic Renal Insufficiency

Publisher Website
Google Scholar
Abstract
In 6 volunteers with normal renal function, we investigated the effects of various kinds of protein (soy, lactoprotein and beef) and various amounts of an intravenously administered amino acid solution on glomerular filtration (GFR) and effective renal plasma flow (ERPF). As for the protein-induced changes in renal function, rises in GFR and ERPF were lowest with soy protein, and highest with beef (baseline GFR, 110 ± 5; soy, 122 ± 5; beef, 131 ± 5 ml/min/1.73 m2; mean ± SEM). High doses of intravenous amino acids induced arise in GFR comparable to that after beef (132 ± 5 ml/min/1.73 m2). In a combined test a liquid mixed meal together with intravenously administered amino acids induced a comparable increase of the GFR (baseline 114 ± 5 versus 129 ± 5 ml/min/1.73 m2). When investigating 9 patients with chronic renal insufficiency after 4 weeks of low protein intake (LP) and after 4 weeks of high protein intake (HP), GFR and ERPF rose significantly under baseline conditions (GFR-LP 41 ± 9 versus GFR-HP 45 ± 9 ml/min/1.73 m2, p < 0.02; ERPF-LP 169 ± 39 versus ERPF-HP 180 ± 40 ml/min/1.73 m2, p < 0.02; paired Wilcoxon). At the end of both dietary periods a comparable rise in renal function could be induced through acute stimulation (GFR-LP 20 ± 5, GFR-HP 16 ± 4; ERPF-LP 23 ± 7, ERPF-HP 22 ± 3%). Glucagon levels tended to fall during a HP diet (glucagon-LP 69 ± 11 versus glucagon HP 50 ± 12 ng/l), whereas an acute rise in glucagon levels could be induced by acute stimulation at the end of both dietary periods (glucagon-LP 163 ± 18, glucagon-HP 173 ± 58%). We conclude that renal function remains variable even in patients with moderate to severe renal insufficiency and that acute stimulation remains possible to the same extent after LP and HP intake. Our results also suggest different underlying mechanisms for the acute and chronic stimulation of renal function.