LIPOCALIN-TYPE PROSTAGLANDIN-D SYNTHASE IN HUMAN MALE REPRODUCTIVE-ORGANS AND SEMINAL PLASMA

Prostaglandin D synthase (PGDS) activity was detected in human seminal plasma (0.05-1.83 nmol/min per milligram protein). The enzyme was pur ified from human seminal plasma by immunoaffinity chromatography and f ound to be 27 kDa in size and N-glycosylated, similar to PGDS in the c erebrospinal fluid. The N-terminal amino acid sequence of 16 residues of the seminal enzyme, APEAQVSVQPNFQQDK, was identical to that of the cerebrospinal fluid PGDS. Although PGDS activity and the content deter mined by the immunoassay each highly varied in the seminal plasma, the concentration was significantly (p < 0.001) lower in the oligozoosper mic group (2.47 +/- 0.51 mu g/ml) than in the normozoospermic group (9 .75 +/- 1.49 mu g/ml). Prostaglandin (PG) D-2 was detected in the semi nal plasma (5.00 +/- 0.65 ng/ml) with a positive correlation to the PG DS concentration (p < 0.05), PGD(2) was converted to the J series of P Gs in the seminal plasma with a half-life of 6.5 h. Northern blot anal ysis revealed that mRNA for PGDS was expressed in the testis, prostate , and epididymis. Through immunohistochemistry, PGDS was localized in Leydig cells of the testis and in epithelial cells of the prostate and ductus epididymidis.