Sex dimorphism of human urinary proteins

The present study was conducted with the assumption that, since drastic endocrine differences exist between males and females, there might be differences in the composition of urinary proteins in normal men and women. Urine specimens were collected from five male and six female volunteers between 25 and 45 years of age, all of whom were without apparent disease at the time of collection. The protein fraction was obtained by gel filtration according to the procedure of Edwards et al (Clinical Chemistry 28:941, 1982). Approximately 300 ug of this protein preparation was subjected to two-dimensional electrophoresis according to the procedure of Anderson and Anderson (Proc. Nat. Acad. Sci. USA 74:5421, 1977). Individual protein spots in the gels were visualized by silver staining and were scored qualitatively with respect to the presence or absence of 40 major proteins. Protein spot #15 with a relative pI similar to that of albumin and an apparent molecular weight of 50,000 daltons was present in all of the male specimens but was either absent or present in trace amounts in female specimens. On the other hand, protein spot #38 with a relative pI similar to that of protein spot #15 and albumin and an apparent molecular weight of about 12,000 daltons was present in all of the female specimens but only in two of five male specimens. These results indicate the presence of different protein species in the urine of men and women.