ABSTRACT
The enzyme complex 3b-hydroxysteroid dehydrogenase/delta(5)-delta(4)-isomerase (3beta-HSD) is involved in the biosynthesis of all classes of active steroids. The expression of 3beta-HSD in human uterine endometrium during the menstrual cycle and decidua was examined in an effort to understand its role during ova implantation. 3beta-HSD was weakly expressed in the glandular epithelium of the proliferative phase and moderately expressed in the glandular epithelium of secretory phase of the endometrium. In the decidua of the ectopic pregnancy, 3beta-HSD was strongly expressed. The human uterine endometrial 3beta-HSD was identified as being the same type as the placental 3beta-HSD by RT-PCR and sequence analysis. In addition to the expression of 3beta-HSD, P450scc was expressed in the decidua of the ectopic pregnancy. These results suggest that pregnenolone might be synthesized from cholesterol by P450scc de novo and then, it is converted to progesterone by 3beta-HSD in the uterine endometrium. The data implies that the endometrial 3beta-HSD can use not only the out-coming pregnenolone from the adrenal gland but also the self- made pregnenolone to produce progesterone. The de novo synthesis of progesterone in the endometrium might be a crucial factor for implantation and maintenance of pregnancy.
Subject(s)
Female , Humans , Pregnancy , Cholesterol/chemistry , Cholesterol Side-Chain Cleavage Enzyme/biosynthesis , Decidua/enzymology , Endometrium/enzymology , Gene Expression/physiology , Menstrual Cycle/physiology , Multienzyme Complexes/biosynthesis , Placenta/enzymology , Pregnenolone/biosynthesis , Progesterone/biosynthesis , Progesterone Reductase/biosynthesis , Steroid Isomerases/biosynthesisABSTRACT
Urokinase-type plasminogen activator(uPA) assayed in uteri of cycling and deciduoma bearing rats shows detectable levels of this enzyme in endometrium. Zymographic analysis confirms uPA of decidual tissue and, following artificial induction of decidualisation, uPA activity constantly increases in the decidualising endometrium reaching a peak on day 9 of pseudopregnancy. Endometrial uPA of nonpregnant rats does not show any significant change during estrous cycle. Results are discussed in relation to expression of this activator in endometrium of rats during morphogenesis of decidual cells.