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After administration of pregnenolone-4-C(14) to Holarrhena floribunda leaves, radioactive progesterone was isolated and purified to constant specific activity by chromatography, conversion to a derivative, and recrystallization. The result suggests that the biogenetic sequence leading to progesterone is the same in plants as in animals.

The presence of cholesterol in Solanum tuberosum and Dioscorea spiculiflora plants was demonstrated by gas-liquid chromatography, thin-layer chromatography, isolation and mixed melting point, and purification to constant radioactivity after dilution with authentic cholesterol.

Crystalline lithocholic (3alpha-hydroxycholanic) acid was isolated from a pooled sample of feces from healthy men for the first time. This acid, which occurs in small amounts in human bile, was obtained by alcohol extraction, followed by solvent partition and chromatography. Under these conditions most of the acid was recovered in the form of its methyl ester.

The presence of stigmasterol in tomato fruits was demonstrated. Labeled mevalonic acid was incorporated into this sterol, while sodium acetate was not. The identity of the isolated product was established by rigorous purification to constant specific activity, melting point determinations, and infrared spectrum.