Journal of Lipid Research, Vol. 7, 750-757, November 1966
Copyright © 1966 by Lipid Research, Inc.

Biosynthesis of ⁷-cholesten-3-ol, ^5,7-cholestadien-3-ol, and ⁵-cholesten-3-ol by guinea pig intestinal mucosa in vitro

Robert K. Ockner and Leonard Laster

Section on Gastroenterology, Metabolic Diseases Branch, National Institute of Arthritis and Metabolic Diseases, Bethesda, Maryland

Methods were developed for the separation and determination of the various 27-carbon sterols of intestinal mucosa by means of thin-layer chromatography. Scrapings of the mucosa of the small intestine of guinea pig and rat were shown to incorporate isotope from ¹⁴C-labeled acetate and mevalonate into sterols in vitro. For each substrate this activity was lowest in mucosa from the proximal third of the small intestine and greatest in mucosa from the more distal regions of the small intestine.

The total 27-carbon sterol content of guinea pig mucosa varied only slightly along the length of the small intestine, but the concentration of cholesterol was highest distally. More than 95% of the radioactivity incorporated from acetate-2-¹⁴C into 27-carbon sterols by guinea pig mucosa in 4 hr was recovered as lathosterol and 7-dehydrocholesterol; less than 5% was in cholesterol. The specific activities of the 27-carbon sterols were consistent with the concept that synthesis proceeds from lathosterol to 7-dehydrocholesterol to cholesterol.

Supplementary key words acetate • mevalonate • incorporation • 27-carbon sterols • cholesterol • 7-dehydrocholesterol • lathosterol • guinea pig • rat • small intestine mucosa • proximal • distal • sterol biosynthesis

Submitted on March 13, 1966
Accepted on July 27, 1966

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