A correlated morphometric and biochemical study of estrogen-induced vitellogenesis in male Rana pipiens.

Adult male Rana pipiens were administered estradiol-17 beta to induce vitellogenesis. Liver and blood were taken from control animals and experimental animals on Days 1, 2, 4, 8, 12, 16, and 120 following hormone treatment. Stereological analysis of livers showed that mitochondrial structural parameters remained constant while rough endoplasmic reticulum (RER) parameters increased significantly by 4 days and to more than four times control, or 120-day levels, by 8-16 days. Liver RNA concentration increased 2.5-fold and in parallel with RER, while liver protein and DNA concentrations did not change. Increases in total plasma protein and plasma vitellogenin (Vg) lagged behind increases in liver RER and RNA. Of the total plasma protein, Vg constituted 6% by 4 days, 40% by 12-16 days and less than 2% by 120 days. The half-life of plasma Vg was estimated to be no greater than 22 days. These studies provide the first quantitative correlations between ultrastructural and biochemical changes occurring in frog tissues following estrogen administration.