Tissue specificity: the clinical importance of steroid metabolites in hormone replacement therapy.

Metabolic activations or inactivations of estrogens, progesterone and androgens are important steps towards the understanding of the physiological and the pathological effects of these hormones in the female organism. Analysis of the tissue specific metabolic pathways of sex steroids will result in a better understanding of successful hormone replacement therapy on the one hand and of the occurrence of steroid hormone related side effects on the other hand. In this contribution we analyse the different mechanisms involved in the synthesis of tissue specific metabolites and discuss the therapeutical importance of these metabolites in hormone replacement therapy.