Estrogen sulfates

Conjugated equine estrogens (Premarin) are the most commonly used estrogens in the treatment of menopause-associated vasomotor symptoms and osteoporosis. Premarin is a mixture of estrogen sulfates, including estrone, equilin, and 17-(3-dihydroequilin. The sulfate derivatives are orally active and are cleaved within the body to yield the active, unconjugated estrogen. 

Zhang H, Henion J (1999) Quantitative and qualitative determination of estrogen sulfates in human urine by liquid chromatography/tandem mass spectrometry using 96-well technology. Anal Chem 71 3955-3964... 

In vitro studies have been conducted to determine the effect of estrogens on kynurenine aminotransferase, which catalyzes the B(,-dependent transamination of kynurenine to ky-nurenic acid. Some estrogen conjugates (e.g.. c.stradiol disulfate and diethylstilbestrol sulfate) interfere with this transamination, apparently hy reversible inhibition of the aminotransfera.se apoenzyme. Apparently, the estrogen sulfate competes with pyridoxal S-phosphate for interaction with the apoenzyme. In conuast. free estradiol and estrone do not pos.sess this inhibitory property. 

Studies in vitro with rat kidney tissue preparations showed that estrogen sulfates inhibit kynurenine transaminase in a reversible fashion that can be relieved by dialysis (MIO, Mil). Competition of sulfate and phosphate esters of estrogens with PLP for the kynurenine transaminase apoenzyme has been demonstrated (S5). An estrogen effect on this enzyme in vivo was suggested by the finding of higher enzyme activity in the kidneys of adult male rats than in either females or estrogen-treated males (M9, Mil). This difference applied to renal kynurenine transaminase, two-thirds of which is in the soluble fraction and the... 

Mil. Mason, M., and Gullekson, E., Interaction of estrogen sulfates with B -enzymes Evidence for physiological significance. Fed. Proc., Fed. Amer. Soc. Exp. Biol. 19, 170 (I960). 

Estrogen sulfates can be hydrolyzed by sulfatases. Gibian and Bratfisch (1956) have described the occurrence in rat and ox liver of an enzyme hydrolyzing dehydroepiandrosterone hydrogen sulfate and estrone hydrogen sulfate. The enzyme is localized in the microsomes and has not been obtained in a soluble form. Roy (1957) has found that the steroid sulfatase is distinct from arylsulfatase C, although the two enzymes are closely associated. It should be noted that the sulfatase is present in amounts comparable with those of the enzyme system synthesizing steroid sulfates. 

Tsang, C. P. W. (1984). Thin-layer chromatographic separation of estrogen sulfates. J. 

There seems to be a considerable secretion of estrogen sulfates by stallion testes (Raeside, 1969), which raises questions as to its biological function. 

Slauiiwhite (1964) has found good recovery of estrogen sulfates but poor recovery of glucosiduronates from alumina columns,... 

Testosterone produced by the placenta is transferred to the fetus and is conjugated mainly with sulfuric acid, but in contrast to a high sulfatase activity by the placental tissues for ester sulfates of 3/J-hydroxy-As steroids and for estrogen sulfates, the testosterone sulfate is poorly hydrolyzed by placental tissues (French and Warren, 1966). These results confirm that the sulfatase activity in the placental compartment is conditioned by the structure of the sulfate. In addition, the incubation of testosterone sulfate with a placental microsomal preparation failed to show any formation of estrogens (Cheatum et at., 1968). These last results also agree with the absence of aromatization of testosterone sulfate during pregnancy (Baulieu ef al., 1965). 

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