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Progestins block cholesterol synthesis to produce meiosis‐activating sterols
Author(s) -
LINDENTHAL BERNHARD,
HOLLERAN ANNE L.,
ALDAGHLAS TAYSEER A.,
RUAN BENFANG,
SCHROEPFER GEORGE J.,
WILSON WILLIAM K.,
KELLEHER JOANNE K
Publication year - 2001
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.00-0214com
Subject(s) - pregnenolone , desmosterol , medicine , demethylation , endocrinology , cholesterol , chemistry , meiosis , sterol , lathosterol , biology , biochemistry , steroid , campesterol , hormone , gene , dna methylation , gene expression
The resumption of meiosis is regulated by meiosis‐preventing and meiosis‐activating substances in testes and ovaries. Certain C 29 precursors of cholesterol are present at elevated levels in gonadal tissue, but the mechanism by which these meiosis‐activating sterols (MAS) accumulate has remained an unresolved question. Here we report that progestins alter cholesterol synthesis in HepG2 cells and rat testes to increase levels of major MAS (FF‐MAS and T‐MAS). These C 29 sterols accumulated as a result of inhibition of Δ24‐reduction and 4α‐demethylation. Progesterone, pregnenolone, and 17α‐OH‐pregnenolone were potent inhibitors of Δ24‐reduction in an in vitro cell assay and led to the accumulation of desmosterol, a Δ5,24 sterol precursor of cholesterol. A markedly different effect was observed for 17α‐OH‐progesterone, which caused the accumulation of sterols associated with inhibition of 4α‐demethylation. The flux of 13 C‐acetate into lathosterol and cholesterol was decreased by progestins as measured by isotopomer spectral analysis, whereas newly synthesized MAS accumulated. The combined evidence that MAS concentrations can be regulated by physiological levels of progestins and their specific combination provides a plausible explanation for the elevated concentration of MAS in gonads and suggests a new role for progestins in fertility.—Lindenthal, B., Holleran, A. L., Aldaghlas, T. A., Ruan, B., Schroepfer, G. J., Jr., Wilson, W. K., and Kelleher, J. K. Progestins block cholesterol synthesis to produce meiosis‐activating sterols. FASEB J. 15, 775‐784 (2001)