A BST RA CT The oxidation and turnover of plasma glycerol has been studied in lean and obese, fed and starving man by means of a long-term infusion of glycerol-"4C, and the participation of glycerol in gluconeogenesis has been determined.Under none of the experimental conditions did glycerol contribute more than 10% of the total respiratory C02. Glycerol turnover in fed lean subjects was 106 mmoles/min. Glycerol levels and turnover were higher in the obese subjects and with all subjects after starvation. There was a direct correlation between plasma levels and turnover values for which a regression equation was derived: y = 1556 x + 33.1, when y= turnover in micromoles per minute and x = glycerol level in micromoles per milliliter.Whereas a. direct relation was established between glycerol and FFA levels, the FFA/glycerol turnover ratio was 4.7: 1 in the lean group indicating incomplete hydrolysis of adipose tissue triglycerides.

No abstract

SUMMARY The sterol composition of several varieties of seafood was assayed by gas‐liquid chromatography. Cholesterol is the major sterol (over 90%) in haddock, pollock, salmon, shrimp, and lobster. The predominant sterols in oyster are cholesterol (41%) and 24.methylenecholesterol (26%), and in crab the major sterols are cholesterol (57%) and brassicasterol (37%). Scallop and clam contain a large number of sterols, the predominant one being cholesterol (26 and 37%, respectively). The sterols other than cholesterol give different chromogens in the calorimetric analysis for sterols, which may account in part for the variability in the “cholesterol” values found in the literature.

No abstract

No abstract

No abstract

Rates of turnover and oxidation of plasma free fatty acid (FFA) were determined in unanesthetized dogs during exercise, acute cold exposure and anaphylactic shock, with the aid of a technique involving the continuous infusion of albumin‐bound palmitate‐1‐14C and the simultaneous measurement of O2 uptake, CO2 output and the specific activities of CO2 and FFA. During exercise in normal untrained dogs, plasma FFA supplied 20–30% of the energy, whereas in trained dogs 70–90% of the energy was derived from the FFA oxidation. In resting dogs at room temperature the plasma FFA level was 0.58 μEq/ml with a turnover rate of 18.6 μEq/kg/min of which 22% was immeditely oxidized and contributed 29% to the exhaled CO2. These results were compared with data obtained in pancreatectomized and thyroidectomized dogs. Acute cold exposure (temperature 4–5C) increased the FFA level and turnover rate to 1.02 μEq/ml and 28.0 μEq/kg/min, respectively, of which 33% was immedaitely oxidized, contributing 46% to the exhaled CO2. During anaphylactic shock, blood lactate increased, FFA level and turnover rate were reduced, and the fraction which was immediately oxidized was depressed markedly, i.e., 3–9% of FFA turnover. Sodium lactate infusion, which induces a blood lactate level comparable to that seen in anaphylaxis or nicotinic acid infusion, markedly decreased the level and turnover rate of FFA. However the fraction of turnover oxidized remained the same as during the preinfusion period (range of 21–40%. Exercise or the administration of norepinephrine during anaphylactic shock provided results suggesting that endogenous lactic acid interferes with FFA oxidation, whereas exogenous, lactate had no effect on this oxidation.

The brain of the young rat contains appreciable amounts of desmosterol (24‐dehydrocholesterol). The peak desmosterol concentration is seen during the first week of life and only traces of this sterol are found at 21 days. The spinal cord also contains some desmosterol. Rat brain desmosterol is distributed in the white matter, gray matter and cerebellum and occurs in the same proportion to cholesterol in each of these brain fractions. Rat brain contains a small amount of sterol ester but no appreciable amounts of desmosterol are present in this fraction.Studies carried out in intact animals injected either intraperitoneally or intracerebrally with mevalonic acid‐2‐14C or glucose‐U‐14C indicate the biosynthetic origin or brain desmosterol. Rat brain slices (1舑20 day old) incubated in suitably fortified medium convert sodium acetate‐2‐14C and glucose‐U‐14C to desmosterol, whereas brain slices from adult rats yielded no radioactive desmosterol under similar conditions. When labeled desmosterol was incubated with young rat brain slices, it was converted to cholesterol.When pregnant rats were treated with triparanol (20 mg/kg/day) during the course of their pregnancy, they either resorbed the fetuses or gave birth to small, stillborn litters. The brains of the progeny of triparanol treated mothers contained large amounts of desmosterol as well as another sterol which may be ख7,24‐cholestadiene‐3ॆ‐ol.