Morfología endometrial y niveles de progesterona en el tejido uterino durante el ciclo estral de vacas cebú

Abstract

The morphophisiologlcal relationships between progesterone and the endometrium must be studied for understanding the metabolic control upon the uterus and the factors affecting embryonic death. The present work was undertaken to analyse the morphological development and the progesterone (P4 ) levels of the endometrium In zebu cattle and to relate the P4 levels with the morphological changes. Thirty three uteri were used and claslfled (17 luteal phase, 16 follicular phase) to take 5 samples of different uterine zones: near the utero-tubal junction, In the middle of the horns and in the uterine body. The samples were analysed microscopically and by radioimmunoassay for P4 . During the luteal phase It was observed that the epithella showed taller cells and a higher number of endometrial glands Indicating an Increased secretory activity. These previous changes are believed to be a consequence of high levels of P4 In blood and In the endometrium. It was also observed an Increase In the number of capillaries during the follicular phase, possibly as a result of the action of estradiol, as stated by some authors. The epithella of the uterine body were lower than the corresponding tissues In the uterine horns. The morphological development of the uterine horns and the P4 levels did not differ when comparing the left with the right horn In all zones studied. The proximal extremities of the uterine horns exhibited more glands and P4 levels but the epithella were not different from the .corresponding tissues In the distal areas. There was a direct relationship between P4 level and epithelial development. It is suggested that the proximal extremities of the uterine horns offer a more adequate environment for embryonic development than any other place In the uterus during the first days of gestation.