[Progestin and estrogen concentrations during the reproduction of sables]

Competitive protein-binding analysis and radioimmune method was applied to the study of the content of progestins and estrogens in the blood and urine in female sables of different age (kept in cages) at periods corresponding to the estrus, diapause and true pregnancy. Sables with a normal course of pregnancy displayed a regular increase in the progestin level already at the period of diapause, although relatively small in value. The period of true pregnancy is attended by a pronounced elevation of the progestine level, with a maximum in the middle of pregnancy. The estrogen level falls at the period of diapause (as compared with the estrus period). The period of true pregnancy is accompanied by a marked elevation of the estrogen level several days before labour, with a fall after them. Examination of the estrogen and progestin levels in sables can aid in the establishment of pregnancy and differentiation of its normal course from the pathological one.