Summary
A primary action of estradiol in the corpus luteum of the pregnant rat is to increase the supply of cholesterol substrate for progesterone production by stimulating cholesterol synthesis, uptake and mobilization (1–3). To determine whether estradiol also affects cholesterol processing, its action of the expression of sterol carrier protein (SCP2) and cytochrome P450SCC, proteins involved in the transport and cleavage of cholesterol, respectively, were investigated. Although mitochondria isolated from luteal cells of estradiol-treated rats secreted significantly more progestagen than the luteal mitochondria from control animals, data presented here indicate that estradiol’s action does not involve stimulation of either the P450SCC message or its content. Whereas estradiol had no effect on P450scc, it caused a marked (threefold) increase in the mitochondrial content of SCP2 as estimated by densitometry of the labelled immune complex on Western blots. The bulk of SCP2 was associated with the mitochondrial fraction of corpora lutea from estradiol-treated rats. In conclusion, increased luteal cell progestagen synthesis by estradiol appears to be directly associated with an increase in mitochondrial SCP2, an effect independent of either luteal P450SCC content or message.
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© 1989 Plenum Press, New York
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McLean, M.P., Puryear, T.K., Khan, I., Billheimer, J.T., Orly, J., Gibori, G. (1989). Steroidal Regulation of Sterol Carrier Protein-2 and P450SCC Expression in the Corpus Luteum. In: Hirshfield, A.N. (eds) Growth Factors and the Ovary. Springer, Boston, MA. https://doi.org/10.1007/978-1-4684-5688-2_49
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DOI: https://doi.org/10.1007/978-1-4684-5688-2_49
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