Prenatal development of leydig cells in nondescript male goats

A study was conducted on the prenatal development of testis on 70 nondescript goat embryos/foetuses procured from a slaughterhouse. The embryos/foetuses were equally categorised into Gr-I (0–30 days), Gr-II (31–60 days), Gr-III (61–90 days), Gr-IV (91–120 days) and Gr-V (121 days -till birth). The genital ridge was observed on 23 ^rd day of gestation. It had accumulation of mesenchymal cells, differentiating fibroblasts and primordial germ cells. The formation of sex cords was evidenced on 44^th day of gestation. Differentiation of Leydig cells started after the appearance of tunica albuginea on 44_th day of gestation. These cells were roughly polygonal in shape and contained highly eosinophilic cytoplasm, spherical nuclei with distinct eccentrically placed nucleolus. At this stage, Leydig cells were present singly. On 56^th day of gestation, Leydig cells were present in groups of 2–3 cells along with differentiating fibroblasts. On the basis of staining characters, size of the nuclei and position of their nucleoli, different forms of Leydig cells (Type-I, II, III and IV) were categorised. The cytoplasm of Type-III Leydig cells showed intense reaction for acid mucopolysaccharides whereas other types exhibited moderate reaction. A study of different stages of the development of Leydig cells would help in understanding the process of spermatogenesis in goats.