Effects of hormone therapy on estrogen synthesis from E1S in the mammary gland of postmenopausal women

Effect of testosterone on E1S-sulfatase activity in non-malignant and cancerous breast cells in vitro

“…T is rapidly aromatized to E2 (and not artificially inhibited like in our study). In contrast, breast tissue having been treated with conventional HT prior to T treatment has already reacted with specific responses like an increased local estrogen formation [45,64], and the additional T is not aromatized to E2 due to product inhibition. This hypothesis is supported by Sikora et al reporting an up-regulation of steroidogenic enzymes under profound estrogen-deprived conditions in vitro.…”

“…STS activity was assessed as previously described [43][44][45]. In brief, all incubations were carried out in duplicates.…”

Effects of black cohosh on estrogen biosynthesis in normal breast tissue in vitro

“…However, in in vivo studies conventional HT, especially estrogen plus progestogen (EPT), has been shown to increase the amount of locally formed estrogens which might at least partly explain the adverse effects on the mammary gland observed by long-term EPT [46,47]. On the other hand, tibolone, a unique tissue-selective agent for postmenopausal women, has been shown to inhibit tumor growth in the therapeutic rat DMBA induced tumor model and to almost abolish tumor development in the preventive model [43].…”

“…In vitro, the effect of steroids on local estrogen formation in normal and malignant breast cells is rather due to changes in STS activity than in its mRNA and protein levels [45]. We recently demonstrated that longterm HT alters local estrogen formation in breast tissue of postmenopausal cynomolgus monkeys (Macaca fascicularis) and women depending on breast tissue composition [46,47].…”