Naslov
Initiation of steroidogenesis precedes expression of cholesterolgenic enzymes in the fetal mouse testes

Autori
Budefeld, T ; Ježek, Davor ; Rozman, D ; Majdič, G

Izvornik
International journal of andrology (0105-6263) 38 (2009), 6; 461-466

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Mouse ; testis ; fetal ; human ; 3beta-hydroxysteroid dehydrogenase ; StAR ; cyp51 ; NADPH cytochrome P450 reductase ; immunocytochemistry

Sažetak
Sexual differentiation is a carefully regulated process that ultimately results in a development of the male or female phenotype. Proper development of the male phenotype is dependent upon the action of testosterone, produced by Leydig cells, and antimullerian hormone, produced by Sertoli cells. Leydig cells start to produce testosterone around day 12.5 in the fetal mouse testis, and continue to produce high levels of testosterone throughout the gestation. In the present study we examined whether expression of two enzymes, lanosterol 14α -demethylase (cyp51) and cytochrome P450 NADPH reductase, involved in the cholesterol production, occurs simultaneously with proteins required for the production of steroid hormones. Immunocytochemical staining with antibodies against lanosterol 14α -demethylase , cytochrome P450 NADPH reductase, steroidogenic acute regulatory protein (StAR) and 3beta- hydroxysteroid dehydrogenase I (3β -HSD I) was used to determine the ontogeny of expression of these four proteins. As expected, 3β -HSD I and StAR proteins were detected on day 12.5 p.c., while expression of cyp51 and NADPH cytochrome P450 reductase appeared one day later, on day 13.5. Thereafter, the expression of all four proteins remained strong throughout the gestation. In human fetal testes, all four proteins were expressed in the Leydig cells at all ages studied, although very young samples from the time of initial Leydig cell development were not examined as they were not available. Results of this study suggest that initial steps of steroid hormone production in murine Leydig cells are dependent on exogenously derived cholesterol. Later on (from day 13.5 onwards), murine and human Leydig cells are able to synthesize cholesterol and are therefore not dependent on exogenous cholesterol resources.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti

POVEZANOST RADA