The post-ovulatory follicles were studied during the annual reproductive cycle and nesting cycle of the pied myna, Sturnus contra contra. These follicles were observed during the breeding phase (May) of the reproductive cycle. Histologically, they were found to regress in 4 stages. Stages I and II were found in the egg-laying period, whereas Stages III and IV were observed in the incubation period of the nesting cycle. The follicles were drastically reduced in the nestling period. 3{3-HSDH activity, present in both granulosa and theca interna of the follicles, was intense during the initial regression Stage (I) and decreased subsequently (Stages II, III and IV). On the other hand, sudanophilic lipid reaction, localized in both layers of the follicles, was weak in Stage I but increased in subsequent Stages (II, III and IV). The findings are briefly discussed.
Post-ovulatory follicle, 3{3-HSDH, Lipid, Pied Myna
