Hormonal steroidogenesis in liver and small intestine of the green frog, Rana esculenta L.

Abstract

We have investigated the potential of autonomous hormonal steroidogenesis in liver and small intestine of male and female frogs, Rana esculenta, during the recovery phase. After incubation of mitochondrial fractions with [4- 14C]cholesterol, female liver and intestine formed pregnenolone at a rate of 0.63 and 2.3 pmol/mg protein/h, respectively, whereas conversion by male organs was only c. 0.03 pmol/mg protein/ h. Minced tissues preparations transformed [4- 14C]pregnenolone into progesterone and 17α-hydroxypregnenolone, the former prevailing in the liver, the latter in the intestine. Moreover, both tissues produced 20α-dihydropregnenolone, 20α-dihydroprogesterone and dehydroepiandrosterone. From incubates with [4- 14C]dehydroepiandrosterone, androstenedione and androst-5-ene-3β, 17β-diol were identified, the former being more abundant in the liver, the latter in the intestine. These results indicate that both liver and intestine in frog can be independent sources of hormonally active steroids in both sexes.