title: Effect of 1α,25-dihydroxyvitamin D3 in plasma membrane targets in immature rat testis: ionic channels and gamma-glutamyl transpeptidase activity.
abstract: 1α,25-Dihydroxyvitamin D(3) (1,25D(3)) is critical for the maintenance of normal reproduction since reduced fertility is observed in vitamin D-deficient male rats. The aim of this study was to investigate the effect of 1,25D(3) in 30-day-old rat testicular plasma membrane targets (calcium uptake and gamma-glutamyl transpeptidase (GGTP) activity), as well as to highlight the role of protein kinases in the mechanism of action of 1,25D(3). The results demonstrated that 1,25D(3) induced a fast increase in calcium uptake in rat testis through a nongenomic mechanism of action. This effect was dependent on PKA, PKC and MEK. Moreover, ionic channels, such as ATP- and Ca(2+)-dependent K(+) channels and Ca(2+)-dependent Cl(-) channels, are involved in the mechanism of action. The use of BAPTA-AM showed that [Ca(2+)](i) was also implicated, and the incubation with digoxin produced an increase in (45)Ca(2+) uptake indicating that the effect of 1,25D(3) may also result from Na(+)/K(+)-ATPase inhibition. In addition, 1,25D(3) was able to increase the GGTP activity. Considered together, our results indicate a PKA/PKC/MEK-dependent 1,25D(3) pathway as well as ionic involvement leading to (45)Ca(2+) uptake in immature rat testis. These findings demonstrate that 1,25D(3) stimulates calcium uptake and increases GGTP activity which may be involved in male reproductive functions.
authors.affiliation: Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil.
authors.forename: Leila
authors.initials: L
authors.lastname: Zanatta
authors.forename: Ariane
authors.initials: A
authors.lastname: Zamoner
authors.forename: Renata
authors.initials: R
authors.lastname: Gonçalves
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Zanatta
authors.forename: Hélène
authors.initials: H
authors.lastname: Bouraïma-Lelong
authors.forename: Camille
authors.initials: C
authors.lastname: Bois
authors.forename: Serge
authors.initials: S
authors.lastname: Carreau
authors.forename: Fátima Regina Mena Barreto
authors.initials: FR
authors.lastname: Silva
mesh_terms: D000818:Animals; D002117:Calcitriol / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D007473:Ion Channels / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013737:Testis / Q000201:enzymology / Q000378:metabolism*; D005723:gamma-Glutamyltransferase / Q000378:metabolism*
chemical_list: D007473:Ion Channels; D005723:gamma-Glutamyltransferase; D002117:Calcitriol