Urinary excretion of human growth hormone: daily variation and relationship with albumin and alpha 1-microglobulin in urine.

Urinary excretion of growth hormone during night-time was measured by a highly sensitive enzyme immunoassay in 6 normal men for 18-24 days. Urinary GH excretion distributed widely from 0.12 to 4.7 pg/mumol creatinine and the coefficient of variation in each subject ranged from 37 to 57% (mean 49%). Urinary excretion of albumin and alpha 1-microglobulin also showed moderate day-to-day variations (mean coefficients of variation: 37 and 42%, respectively). No correlation was found among urinary excretion of GH, albumin and alpha 1-microglobulin. Plasma and urinary GH levels were determined every 5 min and 2 h, respectively, from 09.00 h to 17.00 h in 4 normal men. Urinary GH excretion every 2 h during daytime closely reflected the change of plasma GH levels in each subject, suggesting that physiological GH secretory dynamics are reflected on the urinary GH excretion. Repeated measurements of urinary GH excretion are required to evaluate GH secretory capacity.