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The influence of dietary fat on the biliary bile acid metabolism was studied in a 22-year-old male volunteer by using cholic acid-24-C14. The subject was maintained for 3 successive 15-day periods on homogenized formula diets which provided 45% of calories from butterfat or corn oil, or which were fat-free. The cholic acid turnover was assessed during the final 9 days of each period by analyzing bile samples obtained from the duodenum. On butterfat the daily cholic acid production was 0.13 g, while on corn oil and the fat-free diet it was 0.28 and 0.25 g, respectively. On changing from a free choice to a formula type diet, the glycine/taurine conjugation ratio decreased abruptly from about 2 to nearly 1, and remained at this level as long as the homogenized diet was fed. There was an increase in the proportion of cholic and a corresponding decrease in the deoxycholic acid in the bile with both high fat diets. The reverse changes in these bile acid proportions were associated with the fat-free diet. The fluctuations in the relative concentrations of the other bile acids were less pronounced.

Fifty-eight healthy university students consumed homogenized formula diets for 16 days, and plasma triglycerides were determined on samples of blood obtained from the subjects in the fasting state at days 0, 4, 8, 12, and 16. On a fat-free (high-carbohydrate) diet there was a sex difference in the response, with a group of 11 males showing a highly significant increase (over twofold) and a group of 14 females showing no significant change. No change was observed in 10 male subjects transferred from their free-choice diet to a formula diet providing 45% of calories from butterfat. However, in the case of a group of 23 men who consumed a diet similarly high in corn oil, a significant decrease occurred and the values observed were also significantly lower than those obtained on the butterfat ration. The usual responses of the plasma cholesterol to these diets were observed. Although a parallelism was observed between the behavior of the plasma triglycerides and plasma cholesterol on diets containing fat, there was a divergence on the fat-free diet, characterized by an increase in plasma triglycerides in the males and no change in the females, whereas the usual decrease in plasma cholesterol occurred in both sexes.

A combination of thin-layer chromatography and gas–liquid chromatography was used for the separation and determination of fecal bile acids in three middle-aged men during the last 4 days of three 8-day periods on a fat-free diet. The range of the total output was 130–650 mg/day. Lithocholic and deoxycholic acids were the major components and accounted for 65–80% of the total excretion of bile acids. Other common bile acids were present in considerably smaller quantities (0.5–11% each). In addition, evidence was obtained for the presence of a number of as yet unreported fecal bile acids. These were tentatively identified as 3α,12β-dihydroxy-, 3β,12β-dihydroxy-, 3α,7β-dihydroxy-, 3α-monohydroxy-7-keto-, 12α-monohydroxy-3-keto-, and 7β-monohydroxy-cholanic and cholanic acids. The latter three acids occurred in traces only, but the other uncommon fecal bile acids each accounted for 0.5–7% of the total excretion of bile acids. Significant variations were found in the concentrations of several of the bile acids both between different samples from the same subject and between samples from different subjects.

A method is described for the differential-photometric estimation of coprostanol in faeces, based upon the change in extinction coefficients of cholesterol and coprostanol with time in the Liebermann-Burchard reaction. Recoveries of coprostanol added to artificial sterol mixtures averaged 97.9 ± 6.4% (S.D.). Recoveries after its addition to crude alcoholic extracts of faecal lipids averaged 102.7 ± 4.5%.Corrections can be readily made for the presence of Δ7-stenols by application of the Rosenheim-Callow reaction and a modified Liebermann-Burchard reagent.A distinct advantage of this procedure for coprostanol is the fact that the presence of sitosterol (β- and (or) γ-isomer) does not interfere because its chromogenic behavior in the Liebermann-Burchard reaction enables one to treat it and cholesterol as a single entity despite the relatively large differences in the extinction coefficients.

Material differences in the extinction coefficients of cholesterol and sitosterol (β- and γ-isomer) in the Liebermann-Burchard reaction contrast with the fact that the extinction coefficients of these sterols are identical in the Tschugaeff reaction. This forms the basis for the quantitative differentiation between these sterols by mathematical treatment of data obtained in the two reactions. The principles involved form an extension of analytical steps reported elsewhere for the estimation of 7-dehydrocholesterol, Δ7-cholestenol, and coprostanol.When the concentrations of these five sterols have been determined in faeces excreted by subjects subsisting on formula rations high in corn oil, an estimate of cholestanol plus stigmastanol may be obtained by subtracting the sum of their concentrations from the value for total 3β-hydroxysterol, as determined by the anthrone procedure.Recoveries were as follows: cholesterol, 100.7 ± 7.9%; sitosterol isomers, 99.1 ± 7.6%; cholestanol and (or) stigmastanol, 90.4 ± 10.1%.

The enzymic activities of glucose-6-phosphate dehydrogenase, glutathione reductase, and catalase were studied in the red blood cells of male rats which were fed a basal diet designed to induce acute hepatic necrosis. Significant decreases in the activity were found for all three systems. These changes were prevented by supplementing the basal diet with one of the following: methionine, sodium selenite, DL-α-tocopherol acetate, or all three factors plus cystine.There was no significant change in 6-phosphogluconic dehydrogenase activity when it was investigated under similar circumstances.

The excretion of fecal bile acids was determined in three adult males during the last 4 days of eight dietary periods of 8 days each, during which 35 to 60% of total calories was provided by corn oil or butterfat. The bile acids were identified and individually estimated by a combination of thin-layer and gas chromatography. The total output in two subjects on butterfat (three samples) was 165–288 mg/day, whereas a third subject on a similar diet (two samples) excreted only 38–57 mg/day. On corn oil, the latter subject excreted 37 mg/day of total fecal bile acid and, on mixed corn oil – butterfat diet, 120 mg/day. The low fecal bile acid output in this subject was comparable to that of one of the other two subjects (25 mg/day) on a hydrogenated corn oil diet. The qualitative fecal bile acid patterns were similar with both high-fat diets and resembled those observed earlier on fat-free regimens. Because of the large subject and sample variations, the significance of any quantitative differences in the fecal bile acid excretion with these diets remains in doubt.