Lipogenesis from glucose-2- 14 C and acetate-1- 14 C in aorta

Lipogenesis was measured with glucose-2-(14)C and acetate-1-(14)C in the everted aortas of normal and atherosclerotic rabbits. More glucose-2-(14)C than acetate-1-(14)C was incorporated into lipids in both the normal and the atherosclerotic aorta. Radiocarbon from glucose-2-(14)C appeared mainly in triglycerides and phospholipids with a small amount in cholesteryl esters. Incorporation increased almost threefold with atherosclerosis, most of the radioactivity being in the glycerol moiety; radioactivity was predominantly in carbon 2 of glycerol. About 70% of the acetate-1-(14)C incorporated into phospholipids and triglycerides was in the fatty acids, and the remainder was in glyceride-glycerol; 98% of the radioactivity in cholesteryl esters was in the fatty acid moiety. Incorporation into cholesteryl esters was increased most during the development of atherosclerosis. Fatty acid synthesis was similar from both acetate-1-(14)C and the 2 carbon unit derived from glucose-2-(14)C, viz., predominantly de novo synthesis of fatty acids with 14 and 16 carbon atoms, and elongation for those of 18 carbons and longer.     

Metabolism of ent-kaurenol-[17-14C], ent-kaurenal-[17-14C] and ent-kaurenoic acid-[17-14C] by germinating Hordeum distichon grains

Subcellular fractions from germinated barley embryos, chloroplast preparations and whole germinating barley grains are able to carry out the conversions ent-kaurenol → ent-kaurenal → ent-kaurenoic acid → ent-hydroxykaurenoic acid, the initial steps of the biosynthetic pathway to gibberellins. Whole grains, and chloroplasts to a slight extent, incorporate radioactivity from ent-kaurenol-[17-¹⁴C] and ent-kaurenoic acid-[17-¹⁴C] into materials with similar but distinct properties from the gibberellins GA₁, GA₃, GA₄ and GA₇.     

Metabolism of [1-14C]glyoxylate, [1-14C]-glycollate, [1-14C]glycine and [2-14C]-glycine by homogenates of kidney and liver tissue from hyperoxaluric and control subjects

1. The metabolism of [1-(14)C]glyoxylate to carbon dioxide, glycine, oxalate, serine, formate and glycollate was investigated in hyperoxaluric and control subjects' kidney and liver tissue in vitro. 2. Only glycine and carbon dioxide became significantly labelled with (14)C, and this was less in the hyperoxaluric patients' kidney tissue than in the control tissue. 3. Liver did not show this difference. 4. The metabolism of [1-(14)C]glycollate was also studied in the liver tissue; glyoxylate formation was demonstrated and the formation of (14)CO(2) from this substrate was likewise unimpaired in the hyperoxaluric patients' liver tissue in these experiments. 5. Glycine was not metabolized by human kidney, liver or blood cells under the conditions used. 6. These observations show that glyoxylate metabolism by the kidney is impaired in primary hyperoxaluria.     

Effect of Monofluoroacetate on Pyruvate-3-14C and Glucose-U-14C Incorporation into Ipomeamarone

The olfactory system has a remarkable ability to detect and discriminate a vast variety of odorant molecules. In mammals, hundreds to thousands of odorant receptors (ORs) expressed in olfactory sensory neurons play an essential role in this discrimination. Odorants are recognized by ORs in a combinatorial fashion in which a single odorant activates a particular combination of receptors, leading to its perception as a particular aroma. It is well known that enantiomers emit different aromas in spite of exhibiting otherwise identical chemical properties. To elucidate the molecular basis for the difference, we recorded responses to l- and d-menthol in the mouse olfactory bulb and found that enantiomers elicited similar but overlapping and distinct receptor activation patterns. We then identified l-menthol-specific and d-menthol-biased receptors and performed detailed structure–activity relationship studies, revealing high stereoselectivity of the enantiospecific menthol receptor. The binding site on ORs appears to have evolved to distinguish subtle differences in very similar odorant structures.     

Effect of insulin and cortisol on oxidation of (1-14C)glucose, (6-14C)glucose, (1-14C)palmitate and (1-14C)leucine in the tissues of swine during the neonatal period

The intensity of [1-14C]glucose, [6-14C]glucose, [1-14C]palmitate and [1-14C]leucine oxidation and the effect of insulin and hydrocortisone on this process were studied in the brain, duodenum mucosa, liver and skeletal muscle of 1- and 5-day old piglets in vitro. Most of the studied substrates are oxidized in the tissues of 5-day piglets more intensively. Insulin stimulates oxidation of [1-14C]glucose, [6-14C]glucose and [1-14C]leucine in the brain and duodenum mucosa in 1- and 5-day old piglets, while in the liver and skeletal muscle--only in 5-day old piglets. Hydrocortisone administration enhances oxidation of [1-14C]leucine in most of the studied tissues in 1-day piglets and oxidation of [1-14C]glucose and [6-14C]glucose--in 5-day piglets. Both hormones produce no essential influence on the intensity of [1-14C]palmitate oxidation in the studied tissues of piglets or somewhat weaken it.