Metabolism of Progesterone by Healthy and Inflamed Human Gingiva in Vitro

[4-14C]Progesterone was incubated with homogenate and mitochondrial, microsomal and soluble fraction preparations of healthy and inflamed gingiva from human subjects of both sexes. The subcellular preparations were supplemented with an NADPH-regenerating system and incubated for 2 h at pH 7.4 and 37 degrees C. The metabolites were identified by column, multiple TLC and radioautography and quantified with liquid scintillation counting. In inflamed tissue the metabolic activity was higher than in healthy gingiva. On the basis of the identified metabolites it can be concluded that the human gingiva of both sexes contains marked 3 alpha-, 3 beta- and 20 alpha-hydroxysteroid dehydrogenase, delta 4-5 alpha- and delta 4-5 beta-steroid hydrogenase activities, and less 20 beta-hydroxysteroid dehydrogenase activity.