Development of the ovarian follicles in relation to changes in plasma parameters and ⁵3Δ HSD in snapping turtle, Chelydra serpentina

1. 1. Follicular development in snapping turtle, Chelydra serpentina, was studied in relation to changes in plasma levels of estradiol-17β, total protein, calcium, inorganic phosphate and cholesterol. 2. 2. Histochemical reaction for 3β-HSD in granulosa and theca cells of the follicles is strong during the preovulatory and vitellogenic phases when the follicles attain their maximum size (18-22 mm) and estradiol is at a high level. 3. 3. The reaction for 3β-HSD is weal during the postovulatory phase when the developing follicles are at their minimum size (5-7 mm) and estradiol is low. 4. 4. Administration of estradiol-17β causes a rise in plasma calcium, total protein, inorganic phosphate and cholesterol.