Steroidogenesis female

Occurrence in molluscs of steroidogenesis along a pathway very similar to that found in vertebrates has been claimed. Testosterone (64) - androstenedione (65) interconversion has been demonstrated in gonads of the male and female bivalve - Mytilus edulis [117] and of the gastropod Crepidula fornicata [118], by using labelled testosterone and androstenedione. Moreover, several steroids have been identified in the gonads and hepatopancreas of the opisthobranch... 

ERa Transcriptional Activation AR Binding1 Steroidogenesis H295R Aromatase Recombinant In vivo Uterotrophic Hershberger Pubertal Male Pubertal Female Amphibian Metamorphosis Fish Short-term Reproduction (male female)... 

The maternal-fetal transfer of DEHP and its major metabolite, MEHP, has been demonstrated in rats, and associated with the inhibition of brain and liver steroidogenesis in exposed offspring. In female rats, DEHP administration can suppress estradiol levels and ovulation. A possible mechanism for this effect is the inhibition of the enzymatic formation of estradiol by MEHP. 

Figure 50-9 The regulatory feedback loop of the hypothalamic-pituitary-gonadal axis. Neural and sensory input from the brain elicits the release of Gn-RH. Gn-RH in turn stimulates the synthesis and release of the gonadotropins FSH and LH, which act on the gonads (ovary and testes) to elicit the ripening and ovulation of the ovary and steroidogenesis (estradiol and progesterone) in the female and spermatogenesis and testosterone production in the male. Inhibin formed by the ovaries and testes along with estradiol and testosterone negatively feeds back to the hypothalamic-pituitary axis to modulate Gn-RH, FSH, and LH release.

Biochemical parameters Females decreased serotonin content and increased estradiol and aromatase activity in nerve centres Steroidogenesis (progesterone, testosterone and estradiol- 17p) Increased serotonin and cyclooxygenase activity (prostaglandin production) during spawning... 

Another important source of information on the status of alternative test development, with particular emphasis on the requirements for cosmetics testing, is a review paper published in 2011 by Adler and coauthors [9], Table 1 summarizes those relevant for reproductive toxicity. Several assays refer to the detection of endocrine effects on steroidogenesis based on a variety of cell types, and, as already mentioned, they will be dealt with in another chapter of this book. The other tests can be subdivided in placental toxicity/transport, preimplantation toxicity, female and male toxicity, and developmental toxicity. The tests that are suitable for detecting developmental toxicity include the EST, the whole-embryo assay, the micromass test (all three already described above), the zebrafish embryo teratogenicity assay, and the frog embryo teratogenesis assay (FETAX). 

Leuprolide acetate represents a gonadotropin-releasing hormone agonist tiiat acts as a potent inhibitor of gonadotropin secretion, used as part of the treatment of prostate cancer. Continuous administration results in the suppression of ovarian and testicular steroidogenesis due to decreased levels of LH and FSH with a subsequent decrease in testosterone (male) and oestrogen (female) levels. Leuprolide may also have a direct effect on the testes by a different mechanism not directly related to reduction in serum testosterone. 

In a two-year rat carcinogenicity study with fluconazole, there was a decreased incidence of mammary fibroadenomas in females and adrenal phaeochromocytomas in males. These effects are also thought to be due to inhibition of steroidogenesis, through the inhibition of aromatase. ... 

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