ABSTRACT
The in vivo utilization of D-3-hydroxy[3-14C]butyrate for oxidation in the whole animal and for lipid and amino acid synthesis in brain and spinal cord of overnight-fasted 15-day-old chicks has been measured. Appreciable amounts of injected 3-hydroxy[3-14C]butyrate were expired as 14CO2 one hour after injection, the total amount of which increased with increasing dosages. Lipid synthesis was high in both brain and spinal cord. Free cholesterol and phospholipids were the main lipids labeled in both tissues, increasing with time after injection up to 120 min. The incorporation of radioactivity into triglycerides, esterified cholesterol and free fatty acids was not time-dependent. Increased concentrations of 3-hydroxybutyrate gave rise to higher synthetic rates both in brain and spinal cord. The rate of amino acid synthesis was slightly higher in brain than in spinal cord. Glutamate was always the major amino acid formed.
Subject(s)
Brain/metabolism , Hydroxybutyrates/metabolism , Spinal Cord/metabolism , 3-Hydroxybutyric Acid , Amino Acids/biosynthesis , Animals , Chickens , Cholesterol/biosynthesis , Cholesterol Esters/biosynthesis , Fatty Acids, Nonesterified/biosynthesis , Kinetics , Lipids/biosynthesis , Male , Oxidation-Reduction , Phospholipids/biosynthesis , Triglycerides/biosynthesisABSTRACT
The effect of fasting and refeeding on oxidation, lipogenesis and amino acid synthesis from ketone bodies has been studied in neonatal chick duodenal mucosa. Oxidation and amino acid synthesis were higher from acetoacetate and were stimulated by fasting from both 3-hydroxybutyrate and acetoacetate. On the contrary, lipogenesis was always higher from 3-hydroxybutyrate and fasting reduced lipogenesis rate from acetoacetate (by 66%) but not from 3-hydroxybutyrate. Results suggests the existence of a cytosolic fast-dependent acetoacetyl-CoA synthetase in chick duodenal mucosa which is involved in phospholipid synthesis.
Subject(s)
Acetoacetates/pharmacology , Duodenum/metabolism , Fasting , Hydroxybutyrates/pharmacology , Ketone Bodies/metabolism , Lipids/biosynthesis , 3-Hydroxybutyric Acid , Acetate-CoA Ligase , Acetoacetates/blood , Amino Acids/biosynthesis , Animals , Chickens , Cytosol/enzymology , Hydroxybutyrates/blood , MaleABSTRACT
Changes in fatty acid composition, microsomal delta 9- and delta 6-desaturase activities and liver contents of cholesterol and phospholipids were studied in rats fed medium chain triglyceride-supplemented diets. Weanling rats were divided into four groups and fed for three weeks a basal diet with different 10%-fat supplements: corn oil, medium chain triglyceride-corn oil, olive oil and medium chain triglyceride-olive oil. The highest relative content of saturated fatty acids corresponded to corn oil-fed animals. Both monounsaturated fatty acid content and delta 9-desaturase activity were higher in the animals fed olive oil diets than in corn oil-fed rats. The long chain polyunsaturated fatty acids of the n-3 series were increased in the olive oil and medium chain triglyceride-olive oil-fed groups probably due to the lower linoleic/alpha-linolenic ratios found in these two diets. The cholesterol/phospholipid molar ratio was unaffected by diet and the unsaturation index was only slightly changed in the four groups. Thus, some mechanism may be operative under these conditions to maintain the homeostasis of the membrane.
