The effect of ejaculation on albumin excretion rate.

Microalbuminuria predicts the development of diabetic nephropathy. Large daily variations in albumin excretion rates are frequently observed. Because seminal fluid contains protein and albumin, we reasoned that sexual activity, ejaculation, or residual urethral semen could contribute to albumin content in urine and thus effect determination of albumin excretion rate. Our study was designed to determine the effect of ejaculation of albumin excretion rate and to ascertain if patients routinely should be advised to refrain from sexual activity during or before the urine collection period. Ten normotensive, nondiabetic men (age 31.0 +/- 2.3 years) collected 24-h urine specimens on three occasions: after 3 days of abstinence from sexual activity, during a 24-h period which included one ejaculatory episode, and on a day following sexual activity. Results for albumin excretion rate were: abstinence day: 4.8 +/- 0.7 micrograms/min; sex day: 6.3 +/- 1.1 microgram/min; post-sex day: 4.9 +/- 1.0 micrograms/min. There was no significant difference between these values when compared directly or after log transformation. There also were no differences in urinary creatinine excretion or clearance. We conclude that in nondiabetic individuals ejaculation does not influence albumin excretion rate.