Study of the enzymatic activity of GGT, LDH, PAP and PSA in semen stains: application to age calculation.

The conditions under which semen stains are stored can markedly affect the stability of some of their biochemical parameters. Because of the resistance of semen to processes of degradation and denaturation, the age of the stain may, under optimum conditions, be calculated. We studied six series of semen stain placed on absorbent natural cloth under three different storage temperatures: 5 degrees C (refrigerator), 18-25 degrees C (room temperature), and 38 degrees C (incubator). Seminal fluid was obtained from nonvasectomized and vasectomized individuals aged 25-40 years (mean age 30 +/- 0.32 years, SD 3.06). A total of 240 strains were divided into groups depending on the duration of storage: 24, 48 or 72 h, 1 week, 1, 2, 4 or 6 months. Eluates were analyzed for gamma glutamyltransferase (GGT), lactate dehydrogenase (LDH), prostatic acid phosphatase (PAP), and p30 or prostate specific antigen (PSA). The results of regression analyses showed that a large proportion of the dependent variable (age of the stain) was explained by the rest of the biochemical markers tested. Calculation of the age of the semen stain thus requires consideration of several biochemical parameters.