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A new enzymic determination of GAA in urine

We developed and evaluated a colorimetric method for enzymic determination of guanidinoacetic acid (GAA) in urine. Endogenous urinary urea was first eliminated by urease (EC 3.5.1.5), and the added urease was then removed from the sample by centrifugal ultrafiltration. GAA in the ultrafiltrate was subsequently hydrolyzed by guanidinoacetate amidinohydrolase (EC 3.5.3.2) to glycine and urea. […]

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No effects of GAA on osmotic fragility of erythrocytes

Serum levels of guanidinoacetic acid (GAA) were measured in 22 patients on maintenance hemodialysis prior to dialysis. The mean level was 0.699 ± 0.25 mg/dl, which represents a 3-fold increase above normal. Addition of GAA to blood from normal volunteers and incubation for 3 and 48 h at 37°C did not influence osmotic fragility of […]

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Stimulation of insulin secretion by GAA

Insulin secretion was measured in the isolated perfused rat pancreas in response to guanidinoacetic acid and other guanidine derivatives. Guanidinoacetic acid appears to be more potent than arginine, creatine and guanidine in stimulating insulin secretion. Parasympathetic mediation is unlikely because insulin secretion in response to these compounds is no inhibited by atropine. The guanidino group […]

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GAA and analogues affect mammalian cerebral cortex

Recently, the neuropharmacological action of gama-guanidinobutyric acid, a biochemical constituent of the brain has interested some workers. Purpura et al investigated the effects of guanidinoacids on evoked potentials of themammalian cerebral cortex. Their effects on the crayfish stretch receptor cellwere investigated by Edwards and Kuffler. In the previous paper, the authors investigated the effects of […]

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Growth, muscle creatine and supplemental GAA

A simple and reliable method of extracting creatine from muscle for analysis as creatinine is described. In the absence of exogenous glycocyamine, growth was accelerated but muscle creatine levels were reduced in rats fed folacin and B12, either alone, or with methionine; growth was also accelerated in rats given folacin and B12 with choline, however, […]

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