Low aromatase activity and gene expression in human fetal testes

Tapanainen, Juha S.; Voutilainen, Raimo; Jaffe, Robert B.

doi:10.1016/0022-4731(89)90350-6

Cited by 22 publications

(5 citation statements)

References 34 publications

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“…(26) in fetuses ranging from 10 to 2 5 weeks. In a later study, E2 production by testicular minces was low at all ages between 15 and 23 weeks (27). It could be simulated by hCG in the older ( 19-2 3 week) but not in the younger fetuses (15)(16)(17)(18) week).…”

Section: Discussionmentioning

confidence: 93%

Ontogenesis of estrogen secretion by porcine fetal testes

Raeside

Wilkinson²,

Farkas³

1993

Acta Endocrinologica

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Raeside JI, Wilkinson CR, Farkas G. Ontogenesis of estrogen secretion by porcine fetal testes. Acta Endocrinol 1993;128:549-54. ISSN 0001-5598 High levels of estrogen secretion is a characteristic of steroidogenesis in the pig testis in both the adult and newborn male. We have now examined the ability of fetal gonads to secrete estrogens, and compared it with testosterone secretion during prenatal development. Fetuses were recovered from sows (N=33) at 27\p=n-\114(term) days of gestation. Gonads were removed for organ culture in TC-199 medium, or used as minced tissues or free cell preparations when taken later in development. Organ cultures were maintained for 96 h with luteinizing hormone added for the last 72 h for one gonad of each pair. Estrone, estradiol-1 7\g=b\ and testosterone were measured by radioimmunoassay in media samples. Trace amounts of estrone were detected almost as early as testosterone secretion commenced, but quantities sufficient for confirmation by radioimmunoassay after chromatography were not seen until day 35 of gestation. Estrogen production increased to >0.37 nmol\m=.\gonad-1\m=.\4 h-1 at term. Testosterone secretion in organ culture was increased by luteinizing hormone but no effect was seen on estrone levels for the first half of pregnancy. Thus, estrogen secretion is a feature of steroidogenesis in the porcine testes even in the early stages of fetal development. // Raeside,

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Section: Discussionmentioning

confidence: 93%

Ontogenesis of estrogen secretion by porcine fetal testes

Raeside

Wilkinson²,

Farkas³

1993

Acta Endocrinologica

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“…Also, it is unclear whether hormone levels in cord blood represent well the fetal exposure over a period of nine months (43). It is well-known that testosterone concentrations are highest during weeks 15–18 of gestation and decrease afterwards (44), but it was not practicable for us to collect fetal or cord blood samples during gestation for this study.…”

Section: Discussionmentioning

confidence: 99%

Racial Variation in Sex Steroid Hormones and the Insulin-Like Growth Factor Axis in Umbilical Cord Blood of Male Neonates

Rohrmann

Sutcliffe

Bienstock

et al. 2009

Cancer Epidemiology, Biomarkers &Amp; Prevention

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Background: To address whether umbilical cord blood concentrations of sex steroid hormones and the insulinlike growth factor (IGF) axis differ between AfricanAmerican and White male neonates. Methods: In 2004 and 2005, venous cord blood samples were collected from 75 African-American and 38 White male full-term uncomplicated births along with birth weight, placental weight, mother's age and parity, and time of birth. Testosterone, androstanediol glucuronide, estradiol, and sex hormone binding globulin (SHBG) were measured by immunoassay, and IGF-I, IGF-2, and IGF binding protein (BP)-3 by ELISA. Crude and multivariable-adjusted geometric mean concentrations were computed. Results: Androstanediol glucuronide, estradiol, and SHBG concentrations did not differ by race; however, the molar ratio of testosterone to SHBG was higher in African-American than White male babies after adjust-

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“…There is evidence of aromatase activity as early as 8 weeks of gestation, based on incubation studies using ovarian tissue slices (47). Furthermore, aromatase mRNA expression is present by the second trimester (48). However, the overall expression of all steroidogenic enzymes in the ovary is much lower than that found in the testis at comparable periods of gestation (49).…”

Section: The Ovarymentioning

confidence: 99%

Sexual dimorphism in the neonatal gonad

et al. 1999

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Sexual dimorphism in the neonatal gonad. Acta Paediatr 1999; Suppl 428:23-30. Stockholm. ISSN 0803-5326The neonatal gonad has two distinct forms (i.e., is sexually dimorphic), as judged by morphological and endocrine characteristics. The dimorphic process begins early in embryogenesis. It is well established by the time of birth, by which time the genital ridge has developed into either a testis or an ovary. The mechanisms involved in sex determination involve the Y chromosome, autosomal genes, transcription factors and possibly other unidentified control networks. This review paper describes the morphological changes that occur and the endocrine functions in the developing gonads. It highlights a number of important differences in fetal and neonatal gonadal function. The testis has early histological definition, several determining genes, delayed germ cell maturation, early autonomous steroid secretion, luteinizing hormone (LH) receptor and steroid enzyme expression, high fetal testicular testosterone content, prominent postnatal Leydig and Sertoli cells and high postnatal serum testosterone levels. The ovary has a prolonged monomorphic state, probably one determining gene, germ cells in early meiotic arrest, delayed expression of LH receptor and aromatase, low ovarian oestradiol content, prominent postnatal follicles and low postnatal serum oestradiol levels. 0 Dimorphism, endocrine function, gonads, morphology, ovary, testis During early embryogenesis, the mammalian gonad is monomorphic or indifferent in morphological appearance. The neonatal gonad, however, is sexually dimorphic (i.e., exhibits two distinct forms) in both morphological and endocrine characteristics. This sexual dimorphism of the neonatal gonad is the result of a multitude of genetic factors that effect the switch from a monomorphic to a dimorphic state in early gestation. The genetic switchThe simplistic model that invokes the pivotal role of the Y chromosome in gonadal sexual dimorphism and, hence, sex determination, is shown in Fig. 1. The SRY gene on the short arm of the Y chromosome has been well established, by molecular genetic and clinicopathological studies, as a major player in testis determination (1). Furthermore, autosomal genes are also involved in sex determination, as evidenced by the study of sex reversal syndromes (2-4). The use of targeted gene disruption technology has highlighted the role of transcription factors, such as WT-1 ( 5 ) , SF-1 (6) and LIM-1 (7), in genital ridge development prior to the dimorphic stage.However, disruption of these Y-linked and autosomal genes cannot account for all cases of XY sex reversal, which indicates that additional control networks remain to be identified. Genital ridgeMonomorphic gonad J Ovary XY

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Low aromatase activity and gene expression in human fetal testes

Cited by 22 publications

References 34 publications

Ontogenesis of estrogen secretion by porcine fetal testes

Ontogenesis of estrogen secretion by porcine fetal testes

Racial Variation in Sex Steroid Hormones and the Insulin-Like Growth Factor Axis in Umbilical Cord Blood of Male Neonates

Sexual dimorphism in the neonatal gonad

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