Studies on the Inhibition of Fetal Androgen Formation: Testosterone Synthesis by Fetal and Newborn Mouse Testes<i>in Vitro</i>

Bloch, Eric D.; Lew, Michael J.; Klein, Milton D.

doi:10.1210/endo-88-1-41

Cited by 29 publications

(10 citation statements)

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“…We found lengthening of the anogenital distance, one of the characteristics of virilization, in the aromatase inhibitor-administered group as well. Although fetal adrenal cortex functions are not so active in animals that have a short gestation period, such as rats and rabbits (38), the fetal hypothalamo-pituitary-adrenal system responds to the abnormal maternal conditions during the late gestational period in rats (39,40).…”

Section: Discussionmentioning

confidence: 99%

“…Another possible cause of aromatase deficiency in exhaust-exposed mothers during pregnancy is the reduction of ovarian functions. In rats, progesterone (38) and aromatase activities (41)(42)(43) have been detected at remarkably high levels in pregnant luteal cells in ovaries during pregnancy. In pregnant rats exposed to diesel exhaust, serum progesterone levels were low, and the size and the number of the pregnant corpora lutea were small.…”

Section: Discussionmentioning

confidence: 99%

“…We began administration on day 12 of pregnancy to avoid fetal death, which had occurred in testosterone group 1. The placenta begins secreting testosterone on day 10 of pregnancy (35), and the testes in male embryos differentiate and begin secreting testosterone around the second week of gestation in rats (36)(37)(38). Our timing was designed to ensure that the administered testosterone could act before the hypothalamic-pituitary-gonad axis of the fetuses began to function, which is thought to occur around day 15 of pregnancy (35,39).…”

Section: Methodsmentioning

confidence: 99%

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The masculinization of the fetus during pregnancy due to inhalation of diesel exhaust.

Watanabe¹,

Kurita²

2001

Environ Health Perspect

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This study was conducted to determine the impact of diesel exhaust inhalation on the fetus. Seventy-two pregnant rats and 18 nonpregnant rats were divided into three groups: a group exposed to total diesel engine exhaust containing 5.63 mg/m(3) particulate matter, 4.10 ppm nitrogen dioxide, and 8.10 ppm nitrogen oxide; a group exposed to filtered exhaust without particulate matter; and a group exposed to clean air. The exposure period was from day 7 until day 20 of pregnancy. In addition, 15 pregnant rats were treated with aromatase inhibitors or testosterone to clarify the process by which diesel exhaust exerts its toxicity. The anogenital distance was significantly longer in male and female fetuses from both exhaust-exposed groups than in those of the control. Differentiation of the testis, ovary, and thymus was delayed and disturbed. Maternal testosterone and progesterone levels, which increased due to pregnancy whether or not the rats were exposed, were significantly higher and lower, respectively, in the pregnant rats exposed to total exhaust and filtered exhaust. The serum adrenocorticotropic hormone (ACTH) level and urinary excretion of 17-hydroxycorticosteroids (OHCS) did not differ among the pregnant groups. These results indicate that elevated testosterone did not result from elevated maternal adrenal function. The feto-placental-ovarian unit and inhibition of aromatase activity and synthesis caused by diesel exhaust inhalation might have played an essential role in the accumulation of testosterone. Since both exhaust-exposed groups showed almost the same reactions toward the inhalation, the gaseous phase must have included the relevant toxicants.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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The masculinization of the fetus during pregnancy due to inhalation of diesel exhaust.

Watanabe¹,

Kurita²

2001

Environ Health Perspect

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confidence: 86%

“…The 12-days-old foetal mouse testis synthetizes testosterone (T) in vitro from radioactive precursors (Weniger 8c Zeis 1972). This T synthesis is main¬ tained in the later steps of foetal development, as shown by labelled precursors experiments (Block et al 1971;Pointis et al 1972; Weniger 8c Zeis 1974) and by radioimmunoassay (Pointis 8c Mahoudeau 1974).The role of the foetal pituitary on the testis development and secretion(s) is not clear. Decapitation of the rabbit foetus, performed before the period of genital duct differentiation, results in testicular deficiency which can be sup¬ pressed by gonadotrophin administration (Jost 1951).…”

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confidence: 99%

Demonstration of a Pituitary Gonadotrophin Hormone Activity in the Male Foetal Mouse

Pointis

Mahoudeau

1976

Acta Endocrinologica

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The testosterone production by 18-days-old foetal mouse testis was measured in an organ culture system, by RIA in the culture medium. This production was time-dependent, and could be stimulated by ovine LH and age-matched foetal pituitary. The gonadotrophin activity derived from foetal pituitary appeared to be released into the culture medium as a limited reserve. These data clearly show that a biologically active gonadotrophin material is present in the pituitary of the 18-days-old mouse foetus.In rodents, the male gonad exhibits hormonal activity as soon as the genital ducts undergo differentiation. Castration experiments in the mouse embryo (Raynaud 8c Frilley 1946, 1947a have demonstrated that early testicular secre¬ tion^) are responsible for the development of male genital tract and accessory glands. The 12-days-old foetal mouse testis synthetizes testosterone (T) in vitro from radioactive precursors (Weniger 8c Zeis 1972). This T synthesis is main¬ tained in the later steps of foetal development, as shown by labelled precursors experiments (Block et al. 1971;Pointis et al. 1972; Weniger 8c Zeis 1974) and by radioimmunoassay (Pointis 8c Mahoudeau 1974).The role of the foetal pituitary on the testis development and secretion(s) is not clear. Decapitation of the rabbit foetus, performed before the period of genital duct differentiation, results in testicular deficiency which can be sup¬ pressed by gonadotrophin administration (Jost 1951). In contrast, in rats (Wells

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Comparative Morphology of the Penis and Clitoris in Four Species of Moles (Talpidae)

et al. 2017

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The penile and clitorial anatomy of four species of Talpid moles (broad-footed, star-nosed, hairy-tailed, and Japanese shrew moles) were investigated to define penile and clitoral anatomy and to examine the relationship of the clitoral anatomy with the presence or absence of ovotestes. The ovotestis contains ovarian tissue and glandular tissue resembling fetal testicular tissue and can produce androgens. The ovotestis is present in star-nosed and hairy-tailed moles, but not in broad-footed and Japanese shrew moles. Using histology, 3D reconstruction, and morphometric analysis, sexual dimorphism was examined in regard to a nine feature masculine trait score that included perineal appendage length (prepuce), anogenital distance, and presence/absence of bone. The presence/absence of ovotestes was discordant in all four mole species for sex differentiation features. For many sex differentiation features, discordance with ovotestes was observed in at least one mole species. The degree of concordance with ovotestes was highest for hairy-tailed moles and lowest for broad-footed moles. In relationship to phylogenetic clade, sex differentiation features also did not correlate with the similarity/divergence of the features and presence/absence of ovotestes. Hairy-tailed and Japanese shrew moles reside in separated clades, but they exhibit a high degree of congruence. Broad-footed and hairy-tailed moles reside within the same clade but had one of the lowest correlations in features and presence/absence of ovotestes. Thus, phylogenetic affinity and the presence/absence of ovotestes are poor predictors for most sex differentiation features within mole external genitalia.

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Studies on the Inhibition of Fetal Androgen Formation: Testosterone Synthesis by Fetal and Newborn Mouse Testesin Vitro

Cited by 29 publications

References 0 publications

The masculinization of the fetus during pregnancy due to inhalation of diesel exhaust.

The masculinization of the fetus during pregnancy due to inhalation of diesel exhaust.

Demonstration of a Pituitary Gonadotrophin Hormone Activity in the Male Foetal Mouse

Comparative Morphology of the Penis and Clitoris in Four Species of Moles (Talpidae)

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