Mechanisms of estradiol inactivation in primate endometrium

In uterine endometrium, the level of estradiol is controlled by oxidative 1 7 beta -hydroxysteroid dehydrogenase (17HSD) activity which converts the bi oactive hormone to the less active compound estrone. At least three differe nt types of 17HSD (types 2, 4 and 8) use estradiol as their preferred subst rate and may contribute to the overall rate of estradiol-inactivation in th e uterus. In this study the marmoset monkey (Callithrix jacchus) was used f or the investigation of the particular contribution of each type of 17HSD. Northern Blots revealed essentially the same tissue distribution as in the human. Likewise. uterine 17HSD enzyme activity increases in the secretory p hase of the reproductive cycle. in parallel to the rise in circulating prog esterone levels. Northern analysis of uteri From defined time points of the reproductive cycle showed that only the level of 17HSD2 expression is stro ngly upregulated in the secretory phase, whereas 17HSD4 and 17HSD8 seem to be expressed constitutively. (C) 2001 Elsevier Science Ireland Ltd. All rig hts reserved.