Oestrogens enterohepatic circulation

The metabolites of both oestrogen and progestogen are excreted into the bile. Oestrogen metabolites undergo extensive enterohepatic circulation before being eliminated in the urine. Progestogens do not undergo enterohepatic circulation and their metabolites are excreted mainly in faeces and urine. 

Oestrogens undergo enterohepatic circulation. As this patient is cholestatic, biliary excretion may be impaired. This may reduce the overall exposure to the drug, which could lead to decreased efficacy. However, this was not reported as a problem in the clinical studies involving oral HRT that have been carried out in similar patient populations. 

Enterohepatic circulation of EE may be affected by reduced biliary excretion in cholestasis, resulting in lower oestrogen levels. 

A3. Adlercreutz, H., and Luukkainen, T., Biochemical and clinical aspects of the enterohepatic circulation of oestrogens. Acta Endocrinol. Suppl. 124, 101-140... 

Adlercreutz H. Studies on oestrogen excretion in human bile. Acta Endocrinol. Suppl. (Copenh). 42(Suppl 72), 1-220, 1962. [63b] Sandberg AA, Kirdani RY, Back N, Weyman P, Slaunwhite WR. Biliary excretion and enterohepatic circulation of estrone and estriol in rodents. Am. J. Physiol. 213(5), 1138-1142, 1967. 

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