Prostaglandin F2alpha conceptus-endometrial interaction during early gestation in the mouse

Heat stress on reproductive function and fertility in mammals

In most mammalian species including cattle, heat stress has deleterious effects on nutritional, physiological and reproductive functions. Exposure of animals to a hot environment causes an increase in body temperature in mammals, including domestic animals. High ambient temperature also causes a decrease in the length and intensity of estrus by disturbing ovarian function as well as decreasing pregnancy rate after artificial insemination. Therefore, it is important to understand the effects of heat stress on reproductive function in order to improve the production of domestic animals. Heat stress decreases appetite, weight gain, and milk yield in dairy cattle. It also adversely affects the reproductive performance of both sexes. In males, it reduces spermatogenic activity, while in females it adversely impacts oogenesis, oocyte maturation, fertilization development and implantation rate. Detection and evaluation of the deteriorating effects of heat stress on reproductive organs and cells can help to design measures to prevent them and improve reproductive functions. In this review, we discuss the impacts of heat stress on reproductive functions.

Early embryonic development in the rat after maternal treatment with PGE2

Pregnant Sprague-Dawley rats were treated subcutaneously with PGE2 at doses of 50, 100, and 200 microgram on gestational days five through eight. Control animals received the solvent in a similar manner. On gestational day 9 the animals were killed by intracardiac perfusion with Karnovsky's fixative, uteri were removed, and a transverse central slice from each implantation site was embedded in araldite. The conceptus was located and 2-3 micron sections were made of each implantation site and examined at the light microscopic level. No significant structural changes were induced in any of the conceptuses, but an unusually wide range of embryonic stages was detected in both the control and the experimental groups of animals.