Effects of Progesterone Treatments on Delayed Implantation in Mink
Ova nidation took place in female mink treated with progesterone from the 2nd through the 30th day after mating. When treatments were stopped, the females began to resorb fetuses. Perhaps the treatments partially inhibited natural corpora production of hormones and, when treatments ceased, the corpora could not maintain all the embryos. A lack of progesterone may also have prevented proper breast development, for all kits died within a day or two after birth. The females did not appear to be producing milk. Female mink maintained on progesterone treatments until average gestation length had passed, resorbed or aborted all embryos. Perhaps the treatment was sufficient to inhibit natural production of hormones and was not enough to maintain pregnancy. Treatments of females for one and two days with injected or oral progestins did not inhibit kit production. Some animals that were treated had blastulae implanting or adhering to the uterine endometrium at 18 days after mating. Most of these animals had active corpora and their endometria were moderately developed.
Author Institution: Department of Zoology and Entomology, Ohio Agricultural Research and Development Center, Wooster, Ohio
The Ohio Journal of Science. v67 n1 (January, 1967), 24-31