IMMUNOCYTOCHEMICAL LOCALIZATION OF SEMINAL PROTEINS IN SALIVARY AND LACRIMAL GLANDS OF THE RAT

Antibodies against 10 different secretory proteins from the accessory sex glands of the male rat were used for immunohistochemical studies o f salivary and lacrimal glands from intact and castrated rats, at the light- and electron-microscopic levels. In the parotid gland, secretor y acinar cells showed immunoreactivity with antibodies against prostat ic binding protein, cystatin-related peptide and acid phosphatase (iso enzyme pI 8.0; 5.6) typical of ventral prostate, and seminal vesicle s ecretion VI. Western blotting analysis indicated that immunoreactivity against prostatic binding protein was attributable to a subunit, pres umably C3. Acid phosphatase pi 5.6 showed a molecular weight of 66 kDa , which is at variance with the prostatic form. Immunoreactivity for s ecretory transglutaminase, derived from the coagulating gland, was res tricted to myoepithelial and stromal cells. In castrated animals, the immunoreactivity of acinar cells was reduced to the background level, whereas stromal transglutaminase immunoreactivity was unaltered. The d istribution pattern of immunoreactivity for the proteins mentioned was almost identical in the lacrimal gland. Significant differences were however observed in the immunoreactivity of the inframandibular gland, where serous glandular cells were non-immunoreactive for seminal prot eins, with the exception of acid phosphatase isoenzyme PI 8.0. Granule s present in the convoluted granular ducts were immunoreactive particu larly for acid phosphatase (isoenzyme pi 5.6) but much less for cystat in-related peptide; immunoreactivity was reduced after castration. The straight portion of the inframandibular duct system was immunoreactiv e for transglutaminase, but no influence of castration was visible. Th e distribution of immunoreactivity for seminal proteins present in the salivary and lacrimal glands and the pronounced androgen-dependence o f their expression point to functional relationships of the respective proteins at both glandular sites.