Avtor/Urednik		Majdič, G; Parvinen, M; Bellamine, A; Harwood, HJ; Ku, WW; Waterman, MR; Rozman, D
Naslov		Lanosterol 14alpha-demethylase (CYP51), NADPH-cytochrome P450 reductase and squalene synthase in spermatogenesis: late spermatids of the rat express proteins needed to synthesize follicular fluid meiosis activating sterol
Tip		članek
Vir		J Endocrinol
Vol. in št.		Letnik 166
Leto izdaje		2000
Obseg		str. 463-474
Jezik		eng
Abstrakt		Lanosterol 14alpha-demethylase (CYP51) is a cytochrome P450 enzyme involved primarily in cholesterol biosynthesis. CYP51 in the presence of NADPH- cytochrome P450 redurtase converts lanosterol to follicular fluid meiosis activating sterol (FF-MAS), an intermediate of cholesterol biosynthesis which accumulates in gonads and has an additional function as oocyte meiosis- activating substance. This work shows for the first time that cholesterogenic enzymes are highly expressed only in distinct stages of spermatogenesis. CYP51, NADPH-P450 reductase (the electron transferring enzyme needed for CYP51 activity) and squalene synthase (an enzyme preceding CYP51 in the pathway) proteins have been studied. CYP51 was detected in step 3-19 spermatids, with large amounts in the cytoplasm/residual bodies ofstep 19 spermatids, when p450 reductase was also observed. Squalene synthase was immunodetected in step 2-15 spermatids of the rat, indicating that squalene synthase and CYP51 proteins are not equally expressed in same stages of spermatogenesis. Discordant expression of cholesterogenic genes may be a more general mechanism leading to transient accumulation of pathway intermediates in spermatogenesis. This study provides the first evidence that step 19 spermatids and residual bodies of the rat testis have the capacity to produce MAS sterols in situ.
Deskriptorji		LANOSTEROL NADPH-FERRIHEMOPROTEIN REDUCTASE SPERMATOGENESIS CHOLESTEROL CYTOCHROME P-450 RATS TESTIS SQUALENE SYNTHETASE SPERMATIDS FOLLICULAR FLUID MEIOSIS IMMUNOHISTOCHEMISTRY GERM CELLS LIVER