title: Metabolic factors in the renal response to amino acid infusion.
abstract: In order to investigate the renal effects of amino acids (AA) with different metabolic fate, we compared the changes in glomerular and tubular function, nitrogen metabolism and glucoregulatory hormones in 7 volunteers during two infusions, one of a complete solution of amino acids (MIX-AA), which included five AA electively metabolized at the splanchnic level, and the other of a solution containing only essential AA (EAA), which escape splanchnic metabolism. MIX-AA increased GFR and RPF (from 104 +/- 6 to 122 +/- 13 and from 488 +/- 46 to 572 +/- 34 ml/min/1.73 m2), stimulated splanchnic metabolism as demonstrated by rises in urinary urea excretion (from 20.7 +/- 2 to 30.6 +/- 7.5 mg/min/1.73 m2) and the plasma glucagon/insulin ratio (from 21.4 +/- 13 to 26.7 +/- 15), and caused increases in fractional excretion of AA, FeNa and free-water clearance. During MIX-AA infusion significant correlations were observed between the individual values of GFR and the urea excretion rate (r = 0.66), and between GFR modifications (DeltaGFR) and the plasma glucagon/plasma insulin ratio (r = 0.40). No change in renal function, urea excretion and the glucagon/insulin ratio was observed with EAA. An intermediate splanchnic step (increased plasma glucagon/insulin ratio and ureagenesis) seems necessary in the pathway leading to the nonessential AA-induced rise in GFR; this might stimulate an ultimate intrarenal pathway (possibly involving the diluting segment) via a still undefined mechanism.
authors.affiliation: Department of Pediatrics, University of Milan, Milan, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Claris-Appiani
authors.forename: G
authors.initials: G
authors.lastname: Ardissino
authors.forename: A S
authors.initials: AS
authors.lastname: Tirelli
authors.forename: V
authors.initials: V
authors.lastname: Daccò
authors.forename: C
authors.initials: C
authors.lastname: Corbetta
authors.forename: L
authors.initials: L
authors.lastname: Guidi
authors.forename: E
authors.initials: E
authors.lastname: Moretto
authors.forename: B M
authors.initials: BM
authors.lastname: Assael
authors.forename: F
authors.initials: F
authors.lastname: Sereni
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000008:administration & dosage* / Q000378:metabolism / Q000494:pharmacology; D000601:Amino Acids, Essential / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology; D005919:Glomerular Filtration Rate / Q000187:drug effects; D005934:Glucagon / Q000097:blood; D006801:Humans; D007262:Infusions, Intravenous; D007328:Insulin / Q000097:blood; D007668:Kidney / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009994:Osmolar Concentration; D017595:Renal Plasma Flow / Q000187:drug effects; D014508:Urea / Q000097:blood; D014781:Viscera / Q000378:metabolism
chemical_list: D000596:Amino Acids; D000601:Amino Acids, Essential; D007328:Insulin; D014508:Urea; D005934:Glucagon