摘要:

Rats fed diets with a low (0.3% of total energy) or normal (3%) essential fatty acid (EFA) content were injected intravenously with a single dose of 14C-labelled α-linolenic, arachidonic or oleic acid and the distribution of radioactivity in the tissues was compared 5 min, 1 h and 18 h after the application using whole-body autoradiography. The highest levels of labelling with all fatty acids were observed in the liver, brown fat and adrenal cortex. Specific for arachidonic acid was a high and consistent concentration of radioactivity in the myocardium at all times and for oleic acid in the white fat after 18 h. The tissue uptake of arachidonic acid was similar in both dietary groups, whereas a higher accumulation of α-linolenic was seen in most of the tissues in the low EFA group after 18 h compared to the normal EFA group. The uptake of oleic acid was higher in some tissues in the low EFA than in the normal EFA group after 1 h, but after 18 h these differences had disappeared almost completel

ISSN:0250-6807    

DOI:10.1159/000176963

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The maltase (EC 3.2.1.20)/glucoamylase (EC 3.2.1.3) complex from rat small intestine brush border, which is able to split α (1→4) glucose-sorbitol linkage, was isolated and purified by chromatography on DEAE-Trisacryl M and Sepharose 6B. The complex was homogeneous on polyacrylamide gel electrophoresis. Kinetic parameters were studied on two substrates: maltose and maltitol (Km: 1.3 mM and 30 mM, Vmax: 200 nmol·min-1 and 15 nmol·min-1, respectively). Inhibition studies were performed with maltose and maltitol as substrates and isomaltitol and δ-gluconolactone as inhibitors. Crossed-inhibition reactions were also performed. The results support the existence of one single catalytic site and this fact was confirmed by physicochemical properties. Similar results were obtained with germ-free rats as well as with conventional rats adapted over 6–12 months to Lycasin® 80/55 as the sole source of sugar. Lycasin® 80/55, hydrogenated starch hydrolysate, was converted by purified maltase/glucoamylase complex in glucose and

ISSN:0250-6807    

DOI:10.1159/000176964

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

After feeding marmosets different lipid supplements for 6 months, the distribution of phospholipid classes and the fatty acid composition of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and diphosphatidylglycerol (DPG) were determined in their cardiac membranes. Supplementing the diet with linoleic-acid-rich sunflower seed oil raised the level of 18:2, n-6 in both PC and PE, but did not change the level significantly in DPG. When 18:2, n-6 was increased, the level of arachidonic acid (20:4, n-6) was significantly decreased in PC and PE. No arachidonic acid was present in DPG. Supplementing the diet with mutton fat did not markedly increase the level of saturated fats, nor did it markedly reduce the level of arachidonic acid in any phospholipid component. No dietary treatment altered the distribution of the major phospholipid classes.

ISSN:0250-6807    

DOI:10.1159/000176965

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

Zinc is an essential nutrient for growth and low intake can result in growth retardation. However, high zinc intake can affect copper metabolism. Therefore, data from a study of 10 male premature infants fed a cow’s milk-based formula nonfortified with zinc (mean ± SD = 1.4 ± 0.1 mg·1-1) were compared with data of 10 similar infants fed the same formula fortified with zinc (4.1 ± 0.3 mg·1-1). Growth, food intake, zinc and copper nutritional status were studied from 6 through 122 days of age. No differences in gain of weight, length and head circumference and in food intake were found. Serum zinc concentration was significantly (p < 0.05) and hair zinc concentration was slightly higher in the infants fed the zinc-fortified formula at 122 days of age. Copper and ceruloplasmin concentrations in serum and hair copper concentration were similar in both groups at 122 days of age. The results suggest that feeding a formula nonfortified with zinc did not affect growth of male premature infants. Feeding a zinc-fortified formula on the other hand had no influence on copper nutritional

ISSN:0250-6807    

DOI:10.1159/000176966

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The effects of low copper intake or copper supplementation on the metabolism of stearic acid have been studied previously, but their effects on essential fatty acids have not been reported. Male Sprague-Dawley rats were fed for 12 weeks on pelleted semi-synthetic diets containing < 1 mg/kg copper (low copper), 6 mg/kg (copper control), or 250 mg/kg copper (copper supplemented). The fatty acid composition of the total phopholipids and trigylcerides of plasma, liver, heart and adipose tissue was analyzed by gas liquid chromatography. In low copper rats compared to controls, palmitic and oleic acids were decreased but stearic acid and docosahexaenoic acid were increased in plasma, liver and heart phopholipids. Arachidonic acid was also increased in plasma and liver phospholipids in low copper rats. In liver triglycerides, linoleic and arachidonic acids were increased but palmitic and oleic acid were decreased in low copper rats. Copper supplementation had the opposite effect; palmitic and oleic acids were increased in phospholipids and triglycerides whereas essential fatty acids were generally decreased. Hence, copper not only has a direct effect on the desaturation of stearic acid but also has significant effects on the tissue lipid composition of essential fatty acids.

ISSN:0250-6807    

DOI:10.1159/000176967

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

Supplementation of the diet with 2% cholesterol suppressed the increase observed in the hepatic and intestinal 3-hydroxy-3-methylglutaryl-CoA reductase activity from normally fed chicks during the first days after hatching. Cholestyramine feeding clearly increased both hepatic and intestinal reductase activities. In contrast, brain reductase did not show significant changes by cholesterol or choelstyramine feeding. Dietary cholesterol produced a clear increase in the cholesterol/lipidic phosphorus molar ratio of hepatic and intestinal microsomal membranes. However, this molar ratio did not change by cholestyramine feeding during postnatal development. Both dietary cholesterol and cholestyramine had practically no effect on the cholesterol/lipidic phosphorus molar ratio of brain microsomes. The relationship between the inhibition of reductase activity by dietary cholesterol and the increase of cholesterol/lipidic phosphorus molar ratio is in agreement with a mechanism of regulation of both hepatic and intestinal reductase by alterations of membrane fluidity, mechanism that would be already operative during the neonatal period.

ISSN:0250-6807    

DOI:10.1159/000176968

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The utilization of fructose by isolated hepatocytes was investigated in fed obese Zucker fa/fa rats compared with their lean littermates (Fa/?) and Sprague-Dawley rats. Hepatocytes were incubated during 3 h using U14C fructose (20 mM). Our results show: a significant increase of fructose consumption, glucose, lactate and pyruvate production and faster turnover of glycogen by fa/fa rats. In these animals, synthesis of acylglycerol was also significantly enhanced. Our results suggest that fructose in fa/fa rats was used preferentially as precursor for lipid synthesis not only by the liver but also by the adipose tissue after a prior transformation into glucose by hepatocytes. All these abnormalities result in an accumulation of acylglycerols maintaining an obesity state in fa/fa rats.

ISSN:0250-6807    

DOI:10.1159/000176969

出版商:S. Karger AG    

年代:1985

数据来源: Karger

ISSN:0250-6807    

DOI:10.1159/000176970

出版商:S. Karger AG    

年代:1985

数据来源: Karger