Cytology of the corpus luteum during pregnancy and sexual cycle in cows

Abstract

This study was conducted with the objective of determining the staining properties and light and electron microscopic appearance of the corpus luteum during pregnancy and normal cyclic periods. The samples taken from the corpus luteum of 8 pregnant and 12 non-pregnant cows were used as materials in this study. The corpus luteum was found to be composed of both small and large luteal cells with a rich capillary supply in its tissue. The small luteal cells were found to outnumber large cells in the early periods of pregnancy and in the cyclic corpus luteum while large cells dominated in the latter phases of pregnancy. The large luteal cells had abundant agranular endoplasmic reticulum, mitochondria and secretary granules whereas the small luteal cells had abundant granular endoplasmic reticulum with less mitochondria and secretary granules. As the pregnancy advanced, the large luteal cells in the corpus luteum were noted to have prominent increases in lipid and glycogen granules.