Enterohepatic circulation of estrogens

Metabolism inducible. Enterohepatic circulation of estrogen may be interrupted by alteration in bowel flora (eg, due to antibiotics). 

Ampicillin [NP] Interruption of enterohepatic circulation of estrogen possible reduction in oral contraceptive efficacy. Some other oral antibiotics may have a similar effect. 

Clomiphene citrate, a partial estrogen agonist, is closely related to the estrogen chlorotrianisene (Figure 40-3). This compound is well absorbed when taken orally. It has a half-life of 5-7 days and is excreted primarily in the urine. It exhibits significant protein binding and enterohepatic circulation and is distributed to adipose tissues. 

The increased levels of estradiol stimulate the biosynthesis of the steroid hormone binding protein. The reduction of estriol formation in liver cirrhosis is likely to result in part from cholestasis which interrupts the enterohepatic circulation and in more severe cases from poor uptake of estrogens by the hepatic cells, thus preventing the conversion of estrogen to estriol. 

Metabolic Conjugation and Hydrolysis of Estrogens and Progesterone in the Enterohepatic Circulation... 

METABOLIC CONJUGATION AND HYDROLYSIS OF ESTROGENS AND PROGESTERONE IN THE ENTEROHEPATIC CIRCULATION... 

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