A J Kurischko

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Studies with mice, rats, guinea pigs and baboons were undertaken to define the interceptive action of the new progestin STS 557 (17 alpha -cyanomethyl-17 beta-hydroxy-estra-4.9(10)-diene-3-one) and to compare it with other progestins used in oral contraceptives. STS 557, norethindrone and norethindrone acetate reduced deciduoma formation as well as the(More)
The effect of prostaglandin F2 alpha (PGF2 alpha) on blastocyst implantation in spayed rats has been studied. In preliminary experiments, the first implantation sites were observed 8 - 12 hours after a single injection of estrone in ovariectomized and progesterone-conditioned rats. Intraluminal instillation of PGF2 alpha into the right uterine horn 8 - 10 h(More)
STS 557 (17 alpha-cyanomethyl-17 beta-hydroxy-estra-4.9(10)-diene-3-one) is a potent progestin. This compound was 10 times as potent as the standard levonorgestrel as judged by the classic Clauberg-McPhail Assay. The antiprogestational response is significant when STS 557 treatment starts 2 days before progesterone administration. It does not disturb the(More)
In mice post-coital estrogens caused retardation of tubal egg cleavage, whereas post-coital progestins stimulated egg division. In rats the situation was reversed. In this species estrogens accelerated the tubal embryo development and vice versa; the progestin STS 557 arrested division of embryos resting in the tube. Normal implantation occured following(More)
In immature male Wistar rats levonorgestrel and STS 557 (17 alpha-cyanomethyl-17 beta-hydroxyestra-4,9(10)-diene-3-one) reduced testicular growth, testicular DNA contents and plane of tubular cross-section in a dose dependent manner. In this respect, STS was less active than levonorgestrel. In immature castrated male rats the LH-suppressing effect of STS(More)
Two identified metabolites of the orally active progestin dienogest, the compounds STS 749 (17 alpha-cyanomethyl-11 beta,17 beta-dihydroxy-estra-4,9-dien-3-one) and STS 825 (17 alpha-cyanomethyl-estra-1,3,5(10),9(11)-tetraene-3,17 beta-diol), furthermore 4 microbially formed metabolites and 10 chemically prepared analoga of dienogest were characterized by(More)
STS 557 (17 alpha-cyanomethyl-17 beta-hydroxy-estra-4, 9-dien-3-one) was tested for progestagenic activity in rabbits and for ovulation-inhibiting activities in rabbits and rats in comparison with levonorgestrel and, in some cases, with norethisterone acetate or chlormadinone acetate. In the immature rabbit, the endometrium transformation-inducing activity(More)
STS 557 (17 alpha-cyanomethyl-17 beta-hydroxy-estra-4, 9-dien-3-one) is a interceptive agent in rabbits, mice and rats. In rats, it also shows post-implantational pregnancyterminating activity. In rabbits treated orally before mating or after ovulation for three consecutive days, it inhibited pregnancy largely at total doses of 0.08 mg/kg in the former and(More)
The steroidal estrogens ethinylestradiol, mestranol and the synthetic "impeded" estrogen derivatives STS 456, STS 593 and J 628 were studied for their postcoital antifertility activity and estrogenicity in mice, rats and rabbits. Results of these studies suggest a positive relationship between these two biological endpoints with the exception of the(More)