Progestin in Placental Extract

The effect of certain hormones on the activity of the uterine muscle of the guinea‐pig

“…Hence in the two animals injected with pure progesterone, some eight times the amount fully effective in the mature rabbit was given, and allowing for the difference in the body weight the dose in the guinea-pig was actually more than 50 times that necessary to cause proliferation of the endometrium and desensitization and inhibition of motility in the rabbit. Direct evidence that the doses of progestin used were, at least to some extent, effective in the guinea-pig is shown by the fact that in none of the animals treated with this hormone in addition to cestrin were cestrous changes produced in the vaginal smear-an inhibitory action of progestin similar to that recorded by de Fremery et al [1934] in the mouse.…”

Uterine changes in experimental abortion and their relation to parturition

“…With regard to the first question, the evidence that cestrin is secreted by organs other than the ovary during gestation appears to be conclusive for the human [Ask-Upmark, 1926] and the horse [Hart and Cole, 1934], but there is no evidence whether such is also the case in other species. In the human and the mare, and in addition in the guinea-pig, the corpus luteum is not essential during the whole of pregnancy, but with the exception of the finding by Adler, de Fremery and Tausk [1934] of progestin in the human placenta, there is no evidence as to whether the luteal hormone can be elaborated outside the ovary.…”

“…Indeed, it has been possible by the injection of oestrin during the later stages of pregnancy to induce alterations in the uterine reactivity to oxytocin similar to those obtaining at parturition, thus showing that the luteal function is by then largely in abeyance [Robson, 1935b].In the further investigation of the problem of parturition two important questions have arisen, namely:(1) Are the ovaries the only site of production of the ovarian hormones during pregnancy?(2) What extrinsic factors control the production of the ovarian hormones during pregnancy?With regard to the first question, the evidence that cestrin is secreted by organs other than the ovary during gestation appears to be conclusive for the human [Ask-Upmark, 1926] and the horse [Hart and Cole, 1934], but there is no evidence whether such is also the case in other species. In the human and the mare, and in addition in the guinea-pig, the corpus luteum is not essential during the whole of pregnancy, but with the exception of the finding by Adler, de Fremery and Tausk [1934] of progestin in the human placenta, there is no evidence as to whether the luteal hormone can be elaborated outside the ovary.…”