Effects of Injections of Equine Gonadotrophin upon the Gonads and Adrenals ot Fetal Rats. ∗

Abstract

Using a method recently described. 1 fetuses of the Sprague-Dawley strain of rats were transferred to the abdominal cavity of the mother and subjected to subcutaneous injections of equine gonadotrophin. Thirty-two fetuses received injections twice daily and about 12 hours apart. Near term, the 16 that had survived were secured by severing the umbilical cord. Fourteen and certain littermate controls were immediately autopsied. while 2 were placed in the nest of a foster mother. Although one was promptly destroyed by the mother, the other one received 3 additional injections before it was sacrificed by decapitation (Fetus 20, Table I). Litter 112 (Fetuses 35 and 36) differs from others in that the mother received subcutaneous injections of progesterone for the purpose of delaying parturition. Injections, each containing 1.0 mg, were made twice daily on days 20, 21 and 22 of pregnancy. In all cases, the procedure at autopsy was to open the abdominal cavity before placing the specimen in Bouin's fixing fluid. After fixation, the lumbar and pelvic regions of ihe body were sectioned serially and the sections stained with hematoxylin and eosin. In some instances, certain sections of the series were segregated for special staining (Dominici's. Mallory's triple and Heidenhain's iron hematoxylin).

When sections of testes Tere examined with the aid of a micro-comparator, an instrument which brings half the field of each of 2 microscopes int view, it was found that the interstitial cells of Leydig of each injected mdle mere larger and more abundant than ihoze of litter-mate controls (Fig. 1 to 4). They were most abundant in the 2 fetuses which received the most hormone (3 and 5, Table I).

Although it is reasonable to suppose that the interstitial cells secreted androgen more rapidly than normally (?), evidence that they actually did could not be detected by inspecting serial sections of such developing organs as the prostate, the seminal vesicles and the bulbo-urethral glands. Price and Ortiz'! report that in rats injected after parturition and autopsied on the sixth postnatal day, the combined weight of the seminal vesicles and the coagulating glands was 25% greater than in controls.