Gonadotrophin

Figure 1 A schematic diagram of the endocrine system of fish. TRH = thyrotrophin releasing hormone GnRH = gonadotrophin releasing hormone CRH = corticotrophin releasing hormone TSH = thyroid stimulating hormone GtH = gonadotrophins I and II ...

In premenopausal women the ovary is the richest source of aromatase and hence estrogen. Aromatase is confined to the granulosa cells and is produced under the influence of gonadotropins (FSH and LH). Despite being a rich source of aromatase, three separate studies have shown that aromatase inhibitors are unable to sufficiently suppress ovarian estrogen production to postmenopausal levels. One explanation for this phenomenon may be a compensatory rise in gonadotrophins which maintains adequate estrogen production, despite the presence of the inhibitor. As such aromatase inhibitors cannot be used in premenopausal breast cancer patients. After menopause, ovarian... 

Prolactin is peptide hormone secreted by the pituitary gland. It acts on prolactin receptors in breast tissue where it stimulates production of casein and lactalbu-min. It also acts on the testes and ovaries to inhibit the effects of gonadotrophins. Since the secretion of prolactin is under tonic dopaminergic inhibition by the hypothalamus, dopamine D2-receptor antagonists... 

Periodate Oxidation, Acid Hydrolysis, and Structure-Activity Relationships of Human Pituitary, Follicle-Stimulating Hormone, and Human Chorionic Gonadotrophin, J. F. Kennedy, M. F. Chaplin, and M. Stacey, Carbohydr. Res. 36 (1974) 369-377. 

Singh SK, Pandey RS. 1990. Effect of sub-chronic endosulfan exposures on plasma gonadotrophins, testosterone, testicular testosterone and enzymes of androgen biosynthesis in rat. Indian J Exp Biol 28 953-956. 

FABER K A, HUGHES c L JR. (1993) Dose-responsive characteristics of neonatal exposure to genistein on pituitary responsiveness to gonadotrophin releasing hormone and volume of the sexually dimorphic nucleus of the preoptic area (SDN-POA) in postpubertal castrated female rats. Reprod Toxicol. 1 35-9. 

In some animals, consumption of a phytoestrogen-rich diet can cause temporary infertility and reproductive system disorders (Irvine, 1999). In humans, lower testosterone levels and a decline in human semen quality over the past century have been luiked to increased exposure to environmental endocrine disrupters (EDCs) (Sharpe and Skakkebaek, 1993). Furthermore, cases of sexual impotence have been reported in males exposed to synthetic estrogens in the pharmaceutical industry (Mattison et al., 1990). If this might be the case, the fetal-prepubertal period and Sertoli cell development would be of critical importance (Sharpe and Skakkebaek, 1993). However, an adverse effect of phytoestrogens on male fertility has yet to be proven. Recent work (Mitchell et al., 2001) addressing this point led to the conclusion that up to 40 mg/day of isoflavones over a two-month period had no effects on gonadotrophin and... 

Bronson F., Singer A. and Macrides F. (1988). Chemical properties of a female mouse pheromone that stimulates gonadotrophin secretion in males. Biol Reprod 38, 193-199. 

McDonnell S Diehl N., Garcia M. and Kenney R. (1989). Gonadotrophin releasing hormone (GnRH) affects precopulatory behavior in testosterone-treated geldings. Physiol Behav 45, 145-149. 

A.F. Chetcuti, D.K.Y. Wong, and M.C. Stuart, An indirect perfluorosulfonated ionomer-coated electrochemical immunosensor for the detection of the protein human chorionic gonadotrophin. Anal. Chem. 71, 4088-4094 (1999). 

J. Chen, F. Yan, Z. Dai, and H.X. Ju, Reagentless amperometric immunosensor for human chorionic gonadotrophin based on direct electrochemistry of horseradish peroxidase. Biosens. Bioelectron. 21, 330-336 (2005). 

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