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PubMed1979

Mosaic character of spermatogenesis in carriers of the sex reversed factor in the mouse.

The "sex reversed" factor leads to development of XX male mice. It is inherited on one of the autosomes and transmitted through XY-Sxr carrier males. In the latter, spermatogenesis is studied under the aspect of gene dosis effects produced by the presence of the Sxr factor in addition to the Y chromosome. A mosaic pattern of normal and defective spermatogenesis is described. The defective areas are characterized by failure in late pachytene and metaphase I, and by appearance of spermatids with very large nuclei which degenerate in cap phase. The defects correspond to those observed in X0-Sxr spermatogenesis. Our interpretation is that in the normal areas only the Y chromosome, and in the defective areas the Sxr factor is expressed.

Androgen-Insensitivity Syndrome↗

PubMed1978

Intra-ovarian formation of steroid sulphates: measurement and influence of gonadotrophins.

The steroid sulphokinase activity in 105 000 g supernatant fractions from rat and bovine ovarian tissue has been determined by measuring the radioactivity incorporated into conjugated steroids after incubation with 14C-labelled androgens and oestrogens. The enzyme from bovine ovaries was partially characterized, changes in its activity with pH were measured and Km values of 30, 10 and 4 mumol/1 were obtained for testosterone, oestradiol and oestrone respectively. The rate of formation of sulphates from oestrogens by preparations of bovine luteal tissue was 10--20 times higher than the rate of formation by follicular tissue (P less than 0.001), but both tissues exhibited similar rate of sulphate formation with testosterone. Sulphation of dehydroepiandrosterone by the ovaries of gonadotrophin-treated rats did not differ from that observed in the control group, whereas sulphation of oestrone was nearly three times greater in ovaries obtained from rats treated with gonadotrophins (P less than 0.005). Furthermore, a comparison of steriod sulphation in the ovaries of pseudopregnant and normal cyclic rats showed that the sulphation of oestrone was about six times greater during pseudopregnancy. These observations suggest that the formation of oestrogen, but not androgen, sulphates by ovarian aryl sulphokinase differs in follicular and luteal tissue and may be gonadotrophin dependent. The greater capacity of luteal, compared with follicular, tissue for the sulphation of oestrogens may be a control mechanism for steroidogenesis within the ovarian tissue.

Animals↗