Seasonal Variation in Human Amino Acid Excretion

摘要

Amino acid excretion was studied in young, healthy men during summer, fall, and winter months in a location in southwestern United States. Both random and timed urine samples were employed. The amino acids determined were alanine, arginine, cysteine, glutamic acid, glutamine, glycine, histidine, lysine, methyl histidine, serine, threonine, and valine. Supplemental determinations included urine volume, creatinine, uric acid, urea, sodium, and potassium. Using random samples, and expressing values as ratios with creatinine, significant seasonal variation was found for alanine, arginine, cysteine, glutamic acid, glycine, lysine, serine, urea, and uric acid. Although there was no significant variation in urine volume, both creatinine excretion and the urinary Na/K ratio varied significantly with season. These effects are interpreted as the result of changes in glomerular filtration and tubular reabsorption rates.