title: [In-vitro studies on the effect of D-norgestrel and norethisterone acetate on the formation of sex steroids in the human ovary].
abstract: In vitro incubations with slices of four normal human ovaries and 4-(14)C-pregnenolone as precursor were carried out to study the possibility of a direct influence of D-norgestrel and norethisterone acetate on the metabolism of pregnenolone. In agreement with our previous studies the in vitro-synthesis of progesterone, 17 alpha-hydroxyprogesterone, estrone and estradiol represents the characteristic profile of steroids of the ovaries from the corpus luteum phase. The in vitro-synthesis of 17 alpha-hydroxypregnenolone, DHA, androstenediol (basic metabolites) and androstenedione represents the characteristic profile of steroids of the ovaries from the follicle phase. The addition of D-norgestrel and norethisterone acetate to the incubation medium influences these steroid profiles in the same way. The metabolites of these characteristic profiles were inhibited by the progestogens, whereas the basic metabolites increased. In previous studies the same influence was found by addition of chlormadinone acetate. The influence of these progestagens on the two different profiles of steroids indicate that D-norgestrel and norethisterone acetate exert an inhibitory effect on the 3 beta-hydroxysteroiddehydrogenase-delta 5-4-isomerase system and the aromatase system of the human ovary. These results suggest that these progestogens act directly upon ovarian function, an action which may be assumed to be operative in their contraceptive effect.
mesh_terms: D006907:17-alpha-Hydroxypregnenolone / Q000096:biosynthesis; D000734:Androstenediols / Q000096:biosynthesis; D000735:Androstenedione / Q000096:biosynthesis; D003339:Corpus Luteum Hormones / Q000096:biosynthesis*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D009640:Norethindrone / Q000494:pharmacology*; D009644:Norgestrel / Q000494:pharmacology*; D010053:Ovary / Q000502:physiology
chemical_list: D000734:Androstenediols; D003339:Corpus Luteum Hormones; D006907:17-alpha-Hydroxypregnenolone; D009644:Norgestrel; D000735:Androstenedione; D009640:Norethindrone
vernacular_title: In vitro-Versuche zur Wirkung von D-Norgestrel und Noräthisteronazetat auf die Bildung der Sexualsteroide im menschlichen Ovar.