Immunocytochemical localization of seminal proteins in salivary and lacrimal glands of the rat

Abstract

Antibodies against 10 different secretory proteins from the accessory sex glands of the male rat were used for immunohistochemical studies of salivary and lacrimal glands from intact and castrated rats, at the light- and electron-microscopic levels. In the parotid gland, secretory acinar cells showed immunoreactivity with antibodies against prostatic binding protein, cystatin-related peptide and acid phosphatase (isoenzyme pI 8.0; 5.6) typical of ventral prostate, and seminal vesicle secretion VI. Western blotting analysis indicated that immunoreactivity against prostatic binding protein was attributable to a subunit, presumably C3. Acid phosphatase pI 5.6 showed a molecular weight of 66 kDa, which is at variance with the prostatic form. Immunoreactivity for secretory transglutaminase, derived from the coagulating gland, was restricted 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 distribution 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 proteins, with the exception of acid phosphatase isoenzyme pI 8.0. Granules present in the convoluted granular ducts were immunoreactive particularly for acid phosphatase (isoenzyme pI 5.6) but much less for cystatin-related peptide; immunoreactivity was reduced after castration. The straight portion of the inframandibular duct system was immunoreactive for transglutaminase, but no influence of castration was visible. The distribution of immunoreactivity for seminal proteins present in the salivary and lacrimal glands and the pronounced androgen-dependence of their expression point to functional relationships of the respective proteins at both glandular sites.

Characterization and Cloning of Two Isoforms of Heteroglobin, a Novel Heterodimeric Glycoprotein of the Secretoglobin-Uteroglobin Family Showing Tissue-specific and Sex Differential Expression

“…According to these observations, it has been hypothesized that a structural association exists between members of those subfamilies, and it has also been proposed that one particular SCGB polypeptide can form different heterodimers depending on the available counterparts expressed in the tissue (11,13). For instance, polypeptide C3 forms heterodimers with C1 and C2 in prostatein but has been found to be part of a different protein in rat lacrimal and submaxillary glands (65)(66). Studies on the tissue-specific expression patterns of several members of the two subfamilies support both the necessary co-expression and the possibility of forming different heterodimers (9,13,62,64); like the HGB subunits, most of these SCGBs are expressed in orbital and/or salivary glands.…”

“…The peptides FHG22-(24 -45) and FHG22- (55)(56)(57)(58)(59)(60)(61)(62)(63)(64)(65)(66) contain an extra Cys with respect to the deduced sequence in the carboxyl and amino terminus, respectively, for coupling purposes. The three peptides were coupled to keyhole limpet hemocyanin (Pierce) via Cys using the linking agent Sulfosuccinimidyl 4-(N-maleimido-methyl)cyclohexane-1-carboxylate.…”

Salivary (SD-Type) Cystatins: Over One Billion Years in the Making—But to What Purpose?

“…They have been given a variety of names, including testatin (Eriksson et al, 2002), cystatin-related peptide (CRP; Aumuller et al, 1995), cystatin-related epididymal spermatogenic protein (CRES; Cornwall et al, 1999), and cystatin T (Shoemaker et al, 2000). However, although they possess the PW conserved motif, they lack the conserved N-terminal glycine and consensus QXVXG motif generally required for inhibition of CPs (see below).…”

“…Expression in these tissues is androgendependent, but also requires other unknown testicular factors. Rat CRP1 and 2 are abundant glycoproteins expressed postnatally in the secretory epithelial cells of the ventral prostate, but only CRP1 is expressed in the acinar cells of the parotid (Winderickx et al, 1990;Aumuller et al, 1995;Vercaeren et al, 1998). No expression in the SMG has been detected (Winderickx et al, 1990;Shoemaker et al, 2000).…”

All Human Genes of the Uteroglobin Family Are Localized on Chromosome 11q12.2 and Form a Dense Cluster

“…44 Strong expression in the lung is observed for all orthologous proteins in hamsters, 18 humans, 45 mice, 46 monkeys, 20 hares, 19 pigs, 21 and rats, 47 but strong expression in the uterus seems to be a peculiarity of the Lagomorpha. 19 Expression in the salivary glands has been reported for rabbit uteroglobin, 48 cat Fel dI, 40 rat prostatein C3, 49 FHG22, 36 mouse salivary ABPa, 38 and lacryglobin/mammaglobin B/lipophilin C. 50…”