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H. STEINBECK, F. NEUMANN and W. ELGER

Summary.

From experiments with anti-androgens, it can be concluded which processes in the sex differentiation of dogs are androgen-dependent and which are not. In contrast to rats but as in rabbits, retrogression of the Wolffian ducts can be induced in the treated members of this species compared to their controls, but retrogression of the Müllerian ducts is uninfluenced in both treated and control animals. From this, it is concluded that the latter process is not androgen-dependent.

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H. M. Beier, W. Elger, C. Hegele-Hartung, U. Mootz and K. Beier-Hellwig

Summary. We describe a well-established approach for studying the parameters and mechanisms of synchronization or desynchronization between the maternal and embryonic systems before implantation. It is useful for inducing 'delayed secretion' of the endometrium by different endocrine interventions, which dissociate the endometrial transformation from its control by the corpus luteum. The technique has been achieved by means of direct progesterone antagonists which competitively bind to the progesterone receptor and, in turn, inhibit the physiological effects of progesterone. During the luteal phase, secretory protein patterns indicate the receptive stage of the endometrium. Evidence is presented to show that these patterns, analysed by electro-phoresis and densitometry, define the time at which an embryo transfer is promising for implantation and establishment of pregnancy.

Keywords: uterine proteins; corpus luteum, blastocyst; implantation; progesterone antagonists; human

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G. Singh, M. M. Singh, S. C. Maitra, W. Elger, V. Kalra, S. N. Upadhyay, S. R. Chowdhury and V. P. Kamboj

Summary. RU-38486 or ZK-98734 treatment (3 mg/day, s.c.) to intact or hysterectomized adult female rats on Days 5–7 post coitum induced changes characteristic of luteolysis. Ultrastructurally, the luteal cells exhibited an extensive vacuolization of the cytoplasm and perinuclear areas, degeneration of mitochondrial cristae, massive accumulation of lipid droplets, increase in number of lysosome like granules and heterochromatinization of the nucleus. In general, RU-38486 induced more marked degeneration of the luteal cells than did ZK-98734. There was also a significant decrease in peripheral plasma progesterone concentrations in treated rats. We suggest that these antiprogestagens act via inhibition of luteal function in addition to their antagonism at the uterine progesterone receptor level.

Keywords: antiprogestagens; ultrastructure; corpora lutea; progesterone; rat