A short review on steroid absorption and enterohepatic recycling in man with special emphasis on contraceptive and related steroids is presented. Some new experimental data on the intestinal metabolism of steroids is described and includes further observations on the effect of antimicrobial agents on steroid hormone metabolism. Evidence is presented that plasma levels of steroids may be influenced if the intestinal microflora is altered. Some formation of biologically active steroids, like estradiol, may occur in the intestinal tract and this may have both biological and pathological consequences and may be influenced by such factors as diet and sex. It is concluded that our knowledge of the intestinal and especially, the mucosal metabolism of steroids is scanty and further studies are needed to clarify the role of the intestine and enterohepatic circulation in determining the bioavailability of natural and synthetic steroids.
PIP: The present knowledge on absorption and enterohepatic recycling of contraceptive steroids in human subjects is outlined and some recent results obtained are discussed in this review. The new experimental data relate to the effects of antimicrobial agents on steroid hormone metabolism The plasma levels of steroids may be influenced if the intestinal microflora are altered (as in antibiotic therapy). Some formation of biologically active steroids, such as estradiol, may occur in the intestinal tract and this may be consequential both biologically and pathologically, influenced by factors such as diet and sex. Knowlege of bioavailability of natural and synthetic hormones in terms of their metabolism in the intestine and enterohepatic circulation is scanty. Further studies are called for.