Steroidal Regulation of Sterol Carrier Protein-2 and P450SCC Expression in the Corpus Luteum

  • M. P. McLean
  • T. K. Puryear
  • I. Khan
  • J. T. Billheimer
  • J. Orly
  • G. Gibori


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.


Corpus Luteum Luteal Cell Progesterone Production Sterol Carrier Protein Sterol Carrier 
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  1. 1.
    Gibori G, Chen Y-DI, Khan I, Azhar S, Reaven GM. Regulation of luteal cell lipoprotein receptors, sterol contents, and steroidogenesis by estradiol in the pregnant rat. Endocrinology 1984; 114:609–17.PubMedCrossRefGoogle Scholar
  2. 2.
    Azhar S, Khan I, Chen Y-DI, Reaven GM, Gibori G. Regulation of luteal cell 3-hydroxy-3-methylglutaryl coenzyme A reductase activity by estradiol. Biol Reprod 1985;32:333–41.PubMedCrossRefGoogle Scholar
  3. 3.
    Khan I, Belanger A, Chen Y-DI, Gibori G. Influence of high density lipoprotein on estradiol stimulation of luteal steroidogenesis. Biol Reprod 1985; 32:96–104.PubMedCrossRefGoogle Scholar
  4. 4.
    Yogo N, Kobayaski S, Sekiyama S, et al. Further studies on the submitochondrial localization of cholesterol side chain-cleaving enzyme system in hog adrenal cortex by sonic treatment. J Biochem (Tokyo) 1970; 68:775–83.Google Scholar
  5. 5.
    Scallen TJ, Noland BJ, Garvey KL, et al. Sterol carrier protein 2 and fatty acid-binding protein. J Biol Chem 1985; 260:4733–9.PubMedGoogle Scholar
  6. 6.
    Gibori G, Keyes PL. Role of intraluteal estrogen in the regulation of the rat corpus luteum during pregnancy. Endocrinology 1978; 102:1176–82.PubMedCrossRefGoogle Scholar
  7. 7.
    McLean MP, Khan I, Puryear TK, Gibori G. Estradiol induced synthesis and translation of specific proteins in the corpus luteum. In: Hirshfield A, ed. Paracrine communication in the ovary—ontogenesis and growth factors. New York: Plenum (in press).Google Scholar
  8. 8.
    Heischner S, Kervina M. Subcellular fractionation of rat liver. Methods Enzymol 1974; 31:6–41.CrossRefGoogle Scholar
  9. 9.
    Bradford MN. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem 1976; 72:248–54.PubMedCrossRefGoogle Scholar
  10. 10.
    Laemmli UK. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 1970; 227:680–5.PubMedCrossRefGoogle Scholar
  11. 11.
    Mori M, Marsh JM. The site of luteinizing hormone stimulation of steroidogenesis in mitochondria of the rat corpus luteum. J Biol Chem 1982; 257:6178–83.PubMedGoogle Scholar
  12. 12.
    Towbin H, Staehelin T, Gordon J. Electrophoretic transfer of proteins from Polyacrylamide gels to nitrocellulose sheets: procedure and some applications. Proc Natl Acad Sci USA 1979; 76:4350–4.PubMedCrossRefGoogle Scholar
  13. 13.
    Zlotkin T, Farkash Y, Orly J. Cell-specific expression of immunoreactive cholesterol side-chain cleavage cytochrome P-450 during follicular development in the rat ovary. Endocrinology 1986; 119:2809–20.PubMedCrossRefGoogle Scholar
  14. 14.
    Billheimer JT, Gaylor JL. Cytosolic modulators of activities of microsomal enzymes of cholesterol biosynthesis. J Biol Chem 1980; 255:8128–35.PubMedGoogle Scholar
  15. 15.
    Chirgwin JM, Pryzbyla AE, MacDonald RJ, Rutter WJ. Isolation of biologically active ribonucleic acid from sources enriched in ribonuclease. Biochemistry 1979; 18:5294–9.PubMedCrossRefGoogle Scholar
  16. 16.
    Richards JS, Jahnson T, Hedin L, et al. Ovarian follicular development: from physiology to molecular biology. Recent Prog Hormone Res 1987; 43:231–76.Google Scholar

Copyright information

© Plenum Press, New York 1989

Authors and Affiliations

  • M. P. McLean
    • 1
  • T. K. Puryear
    • 1
  • I. Khan
    • 1
  • J. T. Billheimer
    • 2
  • J. Orly
    • 3
  • G. Gibori
    • 1
  1. 1.Department of Physiology and Biophysics, College of MedicineUniversity of IllinoisChicagoUSA
  2. 2.DuPont Experimental StationWilmingtonUSA
  3. 3.Department of Biological ChemistryHebrew UniversityJerusalemIsrael

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