Sections of the ovaries of elephant fetuses and calves stained immunocytochemically with an anti-3β–HSD antibody. a) Interstitial cells in a fetal ovary at 17.5 months of gestation (Scale bar = 350 μm). b) Higher magnification of the interstitial tissue showing the intense, granular staining for 3β–HSD activity (Scale bar = 40 μm. c) Positively stained interstitial tissue in the ovary of a 2 month old calf (Scale bar = 350 μm). d) 3β–HSD staining of groups of interstitial cells in the ovary of a 2.5 year old calf (Scale bar = 350 μm). e) The granulosa cells of small follicles within the cortex (and medulla in the fetal ovary) stained precisely and strongly for 3β–HSD activity in all the samples examined between 16 months of gestation and 5 years of age (Scale bar = 15 μm). f) Negative control showing the complete ablation of staining following replacement of the primary anti-3βHSD antibody with an unrelated mouse monoclonal antibody (Scale bar = 350 μm).