Steroid-synthesizing cells in the embryonic and adult gonads of the domestic pigeon, Columba livia (Gmelin)

Abstract

Steroidogenic cells in the developing gonads of Columba livia from Day 9 of incubation till the bird attains maturity have been histochemically identified by demonstrating the presence of Δ 5-3 β-hydroxysteroid dehydrogenase (Δ 5-3 β-HSDH). In the embryonic ovary the medulla, containing Δ 5-3 β-HSDH-positive cells, gradually seems to migrate into the cortical region with growth of the embryo and later it dwindles in 15- to 20-day-old hatchlings. In later stages, Δ 5-3 β-HSDH is found in some cells of theca interna of normal follicles, hypertrophied granulosa cells of atretic follicles, the granulosa and theca interna of post-ovulatory follicles, and the interstitial stromal cells. On Day 9 of incubation in the male embryo the convoluted solid seminiferous cords show a weak Δ 5-3 β-HSDH activity. One day prior to hatching, Δ 5-3 β-HSDH activity disappears from the seminiferous cords but appears in the interstitial Leydig cells. In the 4-month-old adult pigeon, Δ 5-3 β-HSDH activity is seen in the Leydig cells as well as in the seminiferous epithelium.