Contraceptives estrogens

Brin, M., Abnormal tryptophan metabolism in pregnancy and with the oral contraceptive pill. I. Specific effects of an oral estrogenic contraceptive steroid on the tryptophan oxygenase and two aminotransferase activities in livers of ovariectomized-adrenalectomized rats. Amer. J. Clin. Nutr. 24, 699-703... 

Mestranol an estrogenic component of oral contraceptive drugs... 

As of 1994, there were approximately 47 progestin-containing contraceptive dmg formulations sold in the United States for use as oral contraceptives (Table 3). In addition, there are three nonoral contraceptive formulations containing progestins ie, one injectable (Depo-Provera), one as an intrauterine device (lUD) (Progestasert), and one implantable (Norplant). Of the oral formulations, all but two also contain an estrogen component, ethynylestradiol. 

The two synthetic steroidal estrogens which have attained the greatest degree of therapeutic use are ethinyl estradiol [57-63-6] (EE) (5) and its 3-methyl ether, mestranol [72-33-3]((5). In contrast to the naturally occurring estrone derivatives, these acetylenic analogues are orally active and are the main estrogenic components of combination oral contraceptives (see Contraceptives) and certain estrogen replacement products. 

Another structural type is chromenes. Centchroman [31477-60-8]is a pyrrolidinoethoxyplienyl chromane which is a potent antiestrogen with weak estrogenic activity. In India, it is used as a weekly contraceptive pih based on its reported abiUty to inhibit the uterine preparation for the attachment of the fertilized ova to the wall of the utems (see Contraceptives) (31). 

Table 1. Low Dose Monophasic Estrogen—Progestogen Combination Oral Contraceptives Marketed in the United States...

Exposure to estrogenic compounds through diet will differ for herbivores and carnivores, the latter being most likely to encounter endogenous steroids in their prey. Efficient uptake of steroids in mammals is illustrated by the use of the contraceptive pill, but routes of absorption in invertebrates remain to be determined. The relationship between endocrine disruption and metabolic toxicity, with reduced reproductive viability a secondary consequence of metabolic disturbance, also merits further study in invertebrate species. 

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