Polymorphism, Dynamics and Ultrastructure of Steroidogenic Cells of Caprine Corpus Luteum

Seven categories of corpora lutea i.e. small ( 1-5 days), medium (6-10 days), large (1115 days), regressing (16-21days) and of previous cycle, penultimate cycle and pregnancy (<30 days) of goat (Capra hircus) were analyzed for cellular polymorphism, dynamics and ultrastructural variations. Histologically, corpus luteum was comprised of two types of steroidogenic cells. The diameter of granulosa luteal cells increased from 33.00 μm in small to 42.00 μm in large category. The theca luteal cells dimensions increased from 19.25 to 28.00 μm. The cell diameters of both these categories of cells showed maxima during pregnancy whereas corpora lutea of previous and penultimate cycles revealed the minimum values. The relative abundance of different types of steroidogenic and non-steroidogenic cells were studied in different reproductive phases of the goat. Blood capillaries and the endothelial cells showed statistically significant variations in different phases. Ultrastructurally, both theca and granulosa luteal cells revealed variations in the relative abundance of different of cell organelles. Mitochondria, smooth endoplasmic reticulum, Golgi complex and secretory granules increased with the increase in granulosa cell diameter during pregnancy. The lysosomes, lipid droplets and vesicles were maximum in the theca luteal cells showing minimum values of diameters in penultimate cycle.