Publications by authors named "Yoshihiko Inaoka"

Diethylstilbestrol (DES), a strong estrogenic compound, is well-known to affect the reproductive system. In this study, we investigated the effects of DES administration on gonadotropin levels and ovarian steroidogenesis in prepubertal rats. DES treatment acutely reduced serum LH levels, followed by a reduction in the expression of various steroidogenesis-related genes in theca cells.

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Alpha 2-HS glycoprotein (AHSG), also designated as fetuin-A, exhibits polymorphism in population genetics consisting of two major alleles of AHSG(∗) 1 and AHSG(∗) 2. The serum level in the AHSG(∗) 1 homozygote is significantly higher than that of the AHSG(∗) 2 homozygote. This study examined the molecular mechanism for the cis-regulatory expression.

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To infer relatedness from genetic data based on short tandem repeats, the exact method, in which shared allele frequencies are applied to relevant equations, has been conventionally used. An alternative approach is the IBS method that is based on the number of shared alleles between individuals. In the present study, the performance of the IBS method in pairwise kinship analysis was compared with the exact method using simulated data of 10,000 genotype pairs for 15 loci in the ABI Identifiler system.

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Previously, we have demonstrated that mesenchymal stem cells could be differentiated into steroidogenic cells through steroidogenic factor-1 and 8bromo-cAMP treatment. Use of liver receptor homolog-1, another of the nuclear receptor 5A family nuclear receptors, with 8bromo-cAMP also resulted in the differentiation of human mesenchymal stem cells into steroid hormone-producing cells. The same approaches could not be applied to other undifferentiated cells such as embryonic stem cells or embryonal carcinoma cells, because the over-expression of the nuclear receptor 5A family is cytotoxic to these cells.

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StAR (steroidogenic acute regulatory protein) mediates the transport of cholesterol from the outer to the inner mitochondrial membrane, the process of which is the rate-limiting step for steroidogenesis. Transcriptional regulation of the proximal promoter of the human StAR gene has been well characterized, whereas analysis of its distal control region has not. Recently, we found that SF-1 (steroidogenic factor 1) induced the differentiation of mesenchymal stem cells (MSCs) into steroidogenic cells with the concomitant strong induction of StAR expression.

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Previously, we demonstrated that bone marrow-derived mesenchymal stem cells (MSCs) differentiate into steroidogenic cells such as Leydig and adrenocortical cells by the introduction of steroidogenic factor-1 (SF-1) and treatment with cAMP. In this study, we employed the same approach to differentiate umbilical cord blood (UCB)-derived MSCs. Despite UCB-MSCs differentiating into steroidogenic cells, they exhibited characteristics of granulosa-luteal-like cells.

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Background: P450 oxidoreductase (POR) catalyzes electron transfer to microsomal P450 enzymes. Its deficiency causes Antley-Bixler syndrome (ABS), and about half the patients with ABS have ambiguous genitalia and/or impaired steroidogenesis. POR mRNA expression is up-regulated when mesenchymal stem cells (MSCs) differentiate into steroidogenic cells, suggesting that the regulation of POR gene expression is important for steroidogenesis.

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NR4A1, also called NGFI-B in the rat, Nur77 in the mouse and TR3 in humans, belongs to the orphan nuclear steroid hormone receptor superfamily and is one of the immediate-early genes. In the endocrine organs, including the gonads, NGFI-B/Nur77 gene expression is rapidly induced by pituitary hormones. NGFI-B/Nur77 expression was found to be rapidly reduced by an estrogenic endocrine disrupter, diethylstilbestrol (DES) in theca interna cells of immature rat ovaries.

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We have shown previously that Cyp11b1, an 11beta-hydroxylase responsible for glucocorticoid biosynthesis in the adrenal gland, was induced by cAMP in androgen-producing Leydig-like cells derived from mesenchymal stem cells. We found that Cyp11b1 was induced in male Leydig cells, or female theca cells, when human chorionic gonadotropin was administered in immature mice. Expression of Cyp11b1 in rodent gonads caused the production of 11-ketotestosterone (11-KT), a major fish androgen, which induces male differentiation or spermatogenesis in fish.

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