The pathways of cathepsin D in rat epididymis may be regulated by steroid hormones

CARVELLI L; BANNOUD N; AGUILERA C; BARRERA P; MORALES CR; SOSA MA

Villa Carlos Paz (Córdoba)

Congreso; XLIV Reunión Anual de la Sociedad Argentina de Investigación Bioquímica (SAIB); 2008

SAIB

Mammalian sperm acquire their fertilizing ability as they pass through the epididymal duct. Among several proteins secreted by the epithelium, high amounts of acid hydrolases are found in the lumen of the organ, although their function is still unclear. We have previously demonstrated that expression of mannose-6-P receptors is increased in epididymis of castrated rats, together with an increase of procathepsin D (pcD) secretion, probably as a response to hormonal changes. As the transport and secretion of pcD in other cell types may follow alternative routes, we proposed to study the possible relationship of pcD with expression and transport of prosaposin (pSAP) and its receptor sortilin (Sor) when epididymal cells are submited to hormonal changes. Castrated or normal  rats and RCE-1 cell line were used, and the expression and distribution of epididymal proteins were analyzed by different methods. We corrobored that secretion of  pcD is increased in castrated rats or RCE-1 cells treated with estradiol and interacts with pSap. Likewise, a redistribution of pcD and Sor to the apical membranes was observed in the epithelium of castrated rats. Treatment of RCE-1 cells with NH4Cl  induced retention of pcD but not pSAP indicating that they may reside in different compartments previous to be secreted. We concluded that pcD sorting is influenced by estrogens by regulating different pathways.