Castration induces changes in M6P receptors in rat epididymis. implications in secretion of Cathepsin D

CARVELLI LORENA; BANNOUD NADIA; AGUILERA CAROLINA; MALOSSI ELIAS; SOSA ESCUDERO MIGUEL

San Luis

Congreso; XXVII Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2009

Sociedad de Biología de Cuyo

It is believed that the mammalian epididymis participates in thematuration of the sperm due to its secretory activity. High concentrationsof several secreted acid hydrolases are found in the epididymallumen. Moreover, some of these enzymes are secreted bythe epididymal epithelium in an androgen-dependent fashion. Inthis study, we attempted to discern whether mannose-6-phosphatereceptors (MPRs) regulate transport and secretion of lysosomalenzymes in the rat epididymis, and if these events are altered whenthe animals are subjected to hormonal manipulation. We observedthat expression of cation-dependent- (CD-MPR) and cation-independent-MPR (CI-MPR) increased significantly in caudal epididymisof castrated rats by immunoblot. This increase was corroboratedby quantisation of MPRs, by using binding assays. This changecould be due to androgen deprivation, as a similar effect was observedafter treatment with the anti-androgenic drug Flutamide.Furthermore, we observed that the CD-MPR was redistributed tothe apical area of the epithelium on castrated rats by immunohistochemistry,which is compatible with the redistribution of the receptorstoward lighter fractions in a Percoll gradient. Consistentwith a possible involvement of the CD-MPR in the secretion, weobserved an increase in procathepsin D levels in epididymal fluidafter castration. We conclude, that the CD-MPR might be regulatedby hormones and that this receptor is involved in the secretionof specific enzymes into the rat epididymis.