Morphological studies of norethisterone oxime effect on ovary in rabbits and rats

Abstract

The search for antiimplantation agents has been attracting attention widely. In animal experiment it has been proven, that norethisterone oxime (NETO) showed significant antiimplantation effect with certain antigestogen activity. Rabbits and rats were used in morphological study in order to explore whether NETO also has some effect on the ovary.

20 mature female rabbits and 12 mature female rats were treated with NETO from the first day of pregnancy for three days and sacrificed on the 9th and the 7th day respectively. The ovaries and uteri were examined histologically after staining with HE and PAS, and histochemically (ACP, ALP, 3ß-HSD and SDH).

It was found that NETO showed obvious antigestogen effect. The corpora lutea became flattened and the lutein cells showed obvious vacuolar degeneration. In histochemical examination, the activity of ACP was increased and 3ß-HSD decreased, but ALP and SDH had not changed. The lutein cells showed electronmicroscopically an increase of fat droplets as well as secondary lysosomes in their cytoplasm and a decrease of SER in number. The secretory granules of lutein cells were of various size and electron density, some of them even exhausted. It could be concluded that the biosynthesis of steroid hormone in ovary was blocked due to the inhibition of 3ß-HSD activity, and that NETO might be an effective contraceptive in human beings.

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