INVESTIGADORES
SOSA ESCUDERO Miguel Angel
congresos y reuniones científicas
Título:
Low levels of testosterone affect the oligomerization and secretion of prosaposin in rat epididymis.
Autor/es:
ZYLA L; AGUILERA AC; MALOSSI AE; BANNOUD N; RUIZ AM; SOSA MA; CARVELLI L
Lugar:
San Luis
Reunión:
Congreso; XXX Reunión Anual de la Sociedad de Biología de Cuyo; 2012
Institución organizadora:
Sociedad de Biología de Cuyo
Resumen:
In mammals, sperm
arriving from the testes are stored in the epididymides to acquire their
motility and fertilizing ability. This sperm maturation is favored by the
secretory activity of the epididymal epithelium. The lumen of the organ is
particularly rich in lysosomal proteins. This striking phenomenon seems to be
crucial for acquiring the fertilizing capacity. Prosaposin (PSAP) is the
precursor (65 kDa) of the lysosomal proteins saposins related with the sphingolipid
metabolism. Previous findings show that PSAP (70 kDa) may covalently aggregate
into oligomers (130-250 kDa). Moreover, these oligomers can not be recognized
by the specific receptor (sortilin) and they enter in a yet unknown secretion
pathway. Based on the characteristics of epididymal secretion and considering
the hormonal dependence of this organ, we here evaluated the degree of
oligomerization of PSAP in the rat epididymal fluid of controls, castrated or castrated
followed by testosterone replacement. Samples were analyzed by electrophoresis under
reducing or non-reducing conditions followed by immunoblot. We observed, for
the first time, the presence of PSAP oligomers (250 kDa) in the epididymal
fluid of the three regions of the organ. In turn, it was demonstrated that castration
induces a decrease in secretion of monomeric PSAP (70 kDa) and an increase of
the oligomeric forms along the whole duct. These effects were reversed by hormone
replacement, indicating that testosterone influences on the oligomerization of PSAP,
and consequently affects the secretion of this lysosomal protein in the
epididymal epithelium