Understanding in vivo carbon precursor supply for fatty acid synthesis in leaf tissue

Twenty-four wether lambs were randomly allocated to six treatments to investigate the effect of temperature and dietary lipid supplements on fatty acid synthesis and metabolic activity in sheep. The treatments consisted of four groups exposed to either cold (0 °C) or warm temperature (+23 °C) and given ad libitum access to either a control barley-based diet or with lipid supplementation. Two other groups were placed on the dietary regimen at 0 °C, but pair-fed to intake of animals in the +23 °C environment. At 5 wk, fatty acid synthesis was measured by [1-14C]acetate incorporation into tissue lipids. Cold exposure and dietary lipid supplementation had no effect (P > 0.05) on in vivo fatty acid synthesis rates in either longissimus dorsi or the liver. In both subcutaneous and mesenteric adipose tissue depots, the rate of acetate incorporation into tissue lipid was not significantly affected by cold exposure. In the perirenal fat depot, cold exposure increased (P < 0.05) the rate of fatty acid synthesis, while lipid supplementation decreased (P < 0.05) the rate in all tissue adipose depots. In vitro, mesenteric and perirenal adipose tissues from cold pair-fed animals had higher (P < 0.05) rates of fatty acid synthesis compared to tissues from animals in the warm environment. However, there was no effect of dietary lipid supplementation in these two fat depots. Metabolic heat production, and energy and nitrogen excretion by animals were increased (P < 0.05) by cold exposure while lipid supplementation had the opposite effect (P < 0.05). The relationship between average daily gain and feed intake was linear at both warm and cold environments, but with higher (P < 0.05) average daily gain at all levels of intake in the cold compared to the warm environment. Results indicate that both environment and diet regulate metabolic activity in sheep. However, there were differences in lipogenic response by tissues to the treatments. Key words: Environmental temperature, dietary lipid, fatty acid synthesis, metabolic rate, sheep

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Hepatic lipogenesis in young rats given proteins of different quality

British Journal Of Nutrition ◽

10.1079/bjn19840079 ◽

1984 ◽

Vol 52 (1) ◽

pp. 131-137 ◽

Cited By ~ 11

Author(s):

G. R. Herzberg ◽

Minda Rogerson

Keyword(s):

Fatty Acid ◽

Fatty Acid Synthesis ◽

Protein Quality ◽

Fatty Acid Synthetase ◽

Acid Synthesis ◽

Hepatic Lipogenesis ◽

Atp Citrate Lyase ◽

Specific Activities ◽

Glucose 6 Phosphate Dehydrogenase

1. The effect of feeding casein, lactalbumin, soya-bean protein, gluten or gelatin on hepatic lipogenesis and the levels of hepatic fatty acid synthetase (FAS), glucose-6-phosphate dehydrogenase (EC 1. 1. 1.49; G6PD), malic enzyme (EC 1. 1. 1.40; ME) ATP-citrate lyase (EC 4. 1. 3. 8; CL), acetyl CoA carboxylase (EC 6.4.1.2; ACCx) and glucokinase (EC 2. 7. 1. 2; GK) was examined in young growing rats.2. The total activities of ACCx, FAS, CL, GK, G6PD, GK, ME and fatty acid synthesis in vivo were positively correlated with protein quality.3. The specific activities of ACCx, FAS, CL, G6PD and fatty acid synthesis in vivo were positively correlated with protein quality.4. The specific activities of GK and ME were unrelated to protein quality.5. The results demonstrate a dissociation between ME and hepatic lipogenesis and suggest a role for the NADPH generated by ME which is not related to the needs of fatty acid synthesis.

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Influence of Meal Frequency on in vivo Hepatic Fatty Acid Synthesis, Lipogenic Enzyme Activity, and Glucose Tolerance in the Chicken

Journal of Nutrition ◽

10.1093/jn/105.8.963 ◽

1975 ◽

Vol 105 (8) ◽

pp. 963-971 ◽

Cited By ~ 14

Author(s):

Kathleen L. Muiruri ◽

Dale R. Romsos ◽

Gilbert A. Leveille

Keyword(s):

Enzyme Activity ◽

Fatty Acid ◽

Glucose Tolerance ◽

Fatty Acid Synthesis ◽

Acid Synthesis ◽

Meal Frequency ◽

Lipogenic Enzyme ◽

Hepatic Fatty Acid

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Fatty acid synthesis in adipose tissues of physically trained rats in vivo

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1983.245.1.e8 ◽

1983 ◽

Vol 245 (1) ◽

pp. E8-E13

Author(s):

K. Tokuyama ◽

H. Okuda

Keyword(s):

Adipose Tissue ◽

Fatty Acid ◽

Fatty Acid Synthesis ◽

Physical Training ◽

Dark Period ◽

Acid Synthesis ◽

Free Access ◽

Adipose Tissues ◽

Brown Adipose

The effect of physical training on fatty acid synthesis in vivo was studied. After the rats had free access to a running wheel for 50 days, the rate of fatty acid synthesis estimated using 3H2O in adipose tissues of trained rats was about three times higher than that of sedentary rats in both the light and dark period. The rate of fatty acid synthesis in the liver but not in the brown adipose tissue was also slightly enhanced by physical training. The number of adipocytes was not affected, but the size of adipocytes was reduced by physical training. In trained rats, the rate of fatty acid synthesis in adipocytes whose diameter was similar to that of sedentary rats was about 10 times higher than that of sedentary rats. Within adipose tissue, the rate of fatty acid synthesis correlated positively to the diameter of adipocytes both in the sedentary and trained rats. These findings mean that the adaptive increase in fatty acid synthesis seen in adipocytes of trained rats is not secondary to the reduction in size of adipocytes.

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The role of dietary protein in hepatic lipogenesis in the young rat

British Journal Of Nutrition ◽

10.1079/bjn19810131 ◽

1981 ◽

Vol 45 (3) ◽

pp. 529-538 ◽

Cited By ~ 14

Author(s):

G. R. Herzberg ◽

Minda Rogerson

Keyword(s):

Fatty Acid ◽

Fatty Acid Synthesis ◽

Dietary Protein ◽

Fatty Acid Synthetase ◽

Acid Synthesis ◽

Hepatic Lipogenesis ◽

Hepatic Fatty Acid ◽

Cleavage Enzyme ◽

Glucose 6 Phosphate Dehydrogenase

1. The effect of varying dietary levels of casein (40–140 g/kg) on hepatic lipogenesis and the levels of hepatic fatty acid synthetase (FAS), glucose-6-phosphate dehydrogenase (EC 1.1.1.49; G6PD), malic enzyme (EC 1.1.1.40; ME), citrate cleavage enzyme (EC 4.1.3.8;CCE), acetyl CoA carboxylase (EC 6.4.1.2; AcCx), glucokinase (EC 2.7.1.2; GK), and pyruvate dehydrogenase (PDH) was examined in young, growing rats.2. The activities of AcCx, FAS, G6PD and in vivo fatty acid synthesis were generally found to increase with increased dietary protein.3. The levels of GK and PDH were not related to dietary protein.4. ME decreased with increasing dietary protein.5. The results demonstrate a dissociation between hepatic fatty acid synthesis and ME and suggest that when rats consume low-protein diets the NADPH needed for fatty acid synthesis is generated primarily by ME but that as the level of dietary protein is increased the contribution of ME is reduced while that of the phosphogluconate pathway becomes more important.

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Energy balance in adrenalectomized ob/ob mice: effects of dietary starch and glucose

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1988.255.1.r141 ◽

1988 ◽

Vol 255 (1) ◽

pp. R141-R148 ◽

Cited By ~ 1

Author(s):

B. P. Warwick ◽

D. R. Romsos

Keyword(s):

Fatty Acid ◽

Energy Balance ◽

Wheat Bran ◽

Fatty Acid Synthesis ◽

Plasma Insulin ◽

Acid Synthesis ◽

Energetic Efficiency ◽

Simple Sugar ◽

Dietary Starch

Effects of different carbohydrate types on energy balance, fatty acid synthesis, and plasma insulin concentrations in adrenalectomized ob/ob mice were investigated. Obese (ob/ob) and lean mice adrenalectomized at 4 wk of age received one of four high-carbohydrate powdered diets for 3 wk: stock, glucose, starch, or starch plus wheat bran. Adrenalectomy reduced energy intake of ob/ob mice equally independent of diet type, whereas energetic efficiency, in vivo rates of fatty acid synthesis in liver and white adipose tissue, and plasma insulin concentrations were substantially reduced to approach values in lean mice in all adrenalectomized ob/ob mice except those fed glucose. The ability of adrenalectomy to normalize energy balance in ob/ob mice depends on factors other than the reduced circulating concentration of glucocorticoids alone. Diet composition is a crucial factor, and striking differences exist between semipurified diets containing a simple sugar (glucose) and those containing a complex carbohydrate (starch), with no additional effect of dietary fiber (wheat bran).

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