Effect of Immunization with β-Trace Protein on Testosterone Levels in Animals

Interest in β-trace (β-tr) has been rekindled after the realization that its N-terminal amino acid sequence1 was identical to that of glutathione independent prostaglandin D synthase, sequenced by Urade and coworkers2. It has now been firmly established that β-tr from cerebrospinal fluid (CSF) and this prostaglandin D synthase from brain are identical3, 4, 5, β-tr is found in most abundance in the CSF, where it constitutes 8–10% of the total protein6, 7, in seminal fluid, where it is higher in concentration although much lower as a percentage of total protein8, and in urine9. β-tr is synthesized in the choroid plexus and brain as shown by incorporation of labeled amino acids into β-tr protein, as well as in testis and fimbriae of the fallopian tubes6. By staining with fluorescent antibody, localization of β-tr was shown in oligodendrocytes and in epididymis10. Moreover, by in situ hybridization with antisense RNA, Urade et al11 have shown synthesis of β-tr in leptomeninges and choroid plexus as well as in oligodendrocytes of the adult rat brain. The enzymatic activity association with β-tr also occurs in the epididymis12.