Steroid Metabolism by the Canine Intestine

Abstract

Harri, M.-P., Nienstedt, W. & Hartiala, K. 1970. Steroid Metabolism by the Canine Intestine. II. The Metabolism of Progesterone by the Jejunal Mucosa in Vitro. Scand. J. Gastroent. 5, 415-419.

4-¹⁴C-Progesterone was incubated in the presence of NADPH2 with the homogenate or different subcellular fractions of canine jejunal mucosa. Great qualitative and quantitative differences were found in its metabolism. The homogenate yielded 5α-pregnane-3,20-dione, 20β-hydroxy-4-prcgncn-3-one, 3-hydroxy-5α-pregnan-20-ones and 3β-20-dihydroxy-5α-pregnancs. The microsomes did not form the diols mentioned. The soluble fraction yielded 5α-pregnane-3,20-dione, some unidentified minor intermediates, and two diols of the 5β-series: 3α,20β-dihydroxy-5β-pregnane and 3β,20α-dihydroxy-5β-pregnane. The enzymatic mechanisms involved in the inactivation of absorbed progesterone in the intestinal mucosa are discussed.

Key-words:

• Dogs
• enzymes
• intestine
• metabolism
• microsomes
• mitochondria
• progesterone
• radioisotopes
• ribosomes