Rapid changes in urinary serine and branched-chain amino acid excretion among diabetic patients during insulin treatment.
In a preliminary experiment, we found a good correlation between 24-h urinary amino acid excretion and the 24-h average plasma levels of the same amino acids. Examining diabetics who were just beginning insulin therapy, we found that insulin normalized the abnormally high levels of excretion of branched-chain amino acids and serine. Interestingly, when expressed in terms of mol/g of creatinine, the normalization of serine excretion brought about by insulin was roughly equal to the normalization of glycine excretion brought about by insulin (-0.39 mM/g of creatinine vs. + 0.33 mM/g of creatinine over 24 h). Since plasma serine is primarily produced in the kidneys from glycine, this suggests that insulin affects the regulation of the serine-glycine metabolic pathway. In turn, measurement of urinary serine and glycine may provide a useful gauge of insulin activity in the tissues, including the kidneys.
Sasaki
M
M
First Department of Internal Medicine, Iwate Medical University, Morioka, Japan.
Sato
K
K
Maruhama
Y
Y
D000596:Amino Acids / Q000097:blood / Q000652:urine; D000597:Amino Acids, Branched-Chain / Q000652:urine*; D001786:Blood Glucose / Q000032:analysis; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000188:drug therapy / Q000652:urine*; D002149:Energy Intake; D005260:Female; D006801:Humans; D007328:Insulin / Q000627:therapeutic use; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012694:Serine / Q000652:urine*
D000596:Amino Acids; D000597:Amino Acids, Branched-Chain; D001786:Blood Glucose; D007328:Insulin; D012694:Serine