This study was conducted to examine the mechanism for arachidonic acid (AA) regulation of steroidogenic acute regulatory (StAR) protein expression and the relationship between AA and cAMP in hormone-induced steroidogenesis. Dibutyryl cyclic AMP (Bt(2)cAMP)-stimulated MA-10 Leydig cells were treated with AA and/or the phospholipase A(2) inhibitor, dexamethasone. Dexamethasone significantly reduc...

The steroidogenic acute regulatory protein (StAR) increases the movement of cholesterol from the outer to the inner membrane of adrenal and gonadal mitochondria, thus providing the substrate for steroid hormone biosynthesis. Deletion of 62 amino-terminal aa produces a cytoplasmic form of StAR (N-62 StAR) that lacks the mitochondrial leader sequence but retains full activity and appears to act a...

Congenital lipoid adrenal hyperplasia (lipoid CAH) is the most severe form of CAH, impairing adrenal and gonadal steroidogenesis. Most cases of lipoid CAH are caused by recessive mutations in the gene encoding steroidogenic acute regulatory protein (StAR), a protein that plays an essential role in cholesterol transfer from the outer to inner mitochondrial membrane, thus providing the substrate ...

The circadian clock plays a significant role in many aspects of female reproductive biology, including estrous cycling, ovulation, embryonic implantation, onset of puberty, and parturition. In an effort to link cell-specific circadian clocks to their specific roles in female reproduction, we used the promoter that controls expression of Steroidogenic Factor-1 (SF1) to drive Cre-recombinase-medi...

The corpus luteum (CL) is a transient endocrine organ that secretes progesterone to support early pregnancy. Using in situ hybridization, immunohistochemistry and computer imaging analysis, we have investigated the expression of transforming growth factor beta 1(TGF-beta 1) , its receptors, type I (TbetaR-I) and type II (TbetaR-II) as well as steroidogenic acute regulatory protein (StAR) in the...

Leydig cells are the primary source of androgens in the mammalian testis. It is established that the luteinizing hormone (LH) produced by the anterior pituitary is required to maintain the structure and function of the Leydig cells in the postnatal testis. Until recent years, a role by the thyroid hormones on Leydig cells was not documented. It is evident now that thyroid hormones perform many ...

AIM To investigate the regulatory function of Cox7a2 on steroidogenesis and the mechanism involved in TM3 mouse Leydig cells. METHODS The cDNA of Cox7a2 was cloned from TM3 mouse Leydig cells. It was subcloned to pDsRed-Express-N1 and transfected back into TM3 mouse Leydig cells for Cox7a2 overexpression by transient gene transfection. Steroidogenesis affected by overexpressed Cox7a2 was stud...

Steroidogenic acute regulatory protein (StAR) regulates the rate-determining step of steroidogenesis. StAR is expressed at a very low level in the white matter of the normal human brain, but is highly expressed in several brain neoplasms including oligodendroglioma (OD). The aim of this study was to identify the different patterns of gene expression low-grade OD and high-grade OD. We carried ou...

We investigated in this study the effects of ovine PRL on endocrine functions of cultured murine Leydig tumor cells (mLTC-1). The parameters studied were the activation of signal transduction systems involving cAMP and intracellular free Ca(2+), the expression of Janus kinase 2 (JAK2), expression and function of LH and PRL receptors (R), expression of the steroidogenic acute regulatory (StAR) p...

PURPOSE Foxo3 in female reproduction has been reported to regulate proliferation of granulose cells that form follicles. There are no reports so far that discuss on the role of Foxo3 in males. This study was designed to outline the role of Foxo3 in the testes. MATERIALS AND METHODS Testes from mice at birth to postpartum week (PPW) 5 were isolated and examined for the expression of Foxo3 usin...