Cholesterol biosynthesis. Metabolism of 14(alpha)-hydroxymethly-5-(alpha)-cholest-7-en-3(beta)-ol
Schroepfer, George J.
Master of Arts
[3a- H]-14a-Hydroxymethyl-5a-choiest-7-en-3B-ol, prepared by chemical synthesis, was incubated with rat liver homogenate preparations (1, x g supernatant fraction) . Efficient conversion to cholesterol was observed. Column chromatographic methods for the separation of sterols on silicic acid-Super-Cel columns, silica gel-Super-Celsilver nitrate columns and alumina-Super-Cel-silver nitrate columns were utilized during the course of the above studies. The metabolism of [32- H]-14a-hydroxymethyl-5acholest7-en-3&-ol, prepared by chemical synthesis, was also investigated. The incorporation of the radioactivity into tritiated water was demonstrated by the incubation of this labeled substrate with 1, x g supernatant fraction of rat liver homogenate. The fate of tritium labeled formate ( HCOONa) was investigated by incubation with 1, x g supernatant fraction also and most of the radioactivity recovered after incubation was in the form of tritiated water. The tritium labeled formate was also investigated by incubation with rat liver microsomal preparations in the presence of a TPNH generating system and the results showed that no metabolism of tritium labeled formate could be detected. Therefore, the incubation of the [32- H] labeled substrate with rat liver microsomes was carried out and the results showed that the label of [32- H]-14a-hydroxymethyl-5a-cholest-7-en36-ol was incorporated into formic acid.