ISSN:0250-6807    

DOI:10.1159/000176956

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

In order to study the influence of varying vitamin B6 intake levels on the reproductive performance and the vitamin B6 status of fetuses and reproductive organs, 30 pregnant rats (Sprague Dawley strain) were fed a semisynthetic casein diet supplemented with 1,6, 12, 24 and 48 mg vitamin B6/kg throughout pregnancy. On days 19 of pregnancy the rats were killed. Fetuses, placenta, amniotic fluid, amnion, uterus and mammary gland were analysed microbiologically for their vitamin B6 content. Reproductive performance was not influenced by the dietary treatment. Vitamin B6 concentrations in fetuses, placenta and amniotic fluid of mothers treated with the low 1-ppm vitamin B6 diet were significantly decreased. At a vitamin B6 supply of 6 ppm, however, tissue saturation was already reached in these organs. Accordingly, the whole vitamin B6 retention in the reproductive product plateaued at an intake level of 6 ppm vitamin B6 at 37 μg vitamin B6 per animal. These results indicate therefore that a level of 6 ppm dietary vitamin B6 is sufficient to guarantee an optimum vitamin B6 status in the reproductive product, and higher vitamin B6 supplementations showed no further effect on the parameters investigated.

ISSN:0250-6807    

DOI:10.1159/000176957

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

Rats were conditioned to ingest a 15-gram dietary mixture, in a single daily meal, between 6:00 and 9:00 a.m. Labeled cholesterol was introduced into the organism through four different physiological routes: ingestion of 14C-cholesterol, injection of 14C-acetate, injection of red cells or plasma whose cholesterol was tritium-labeled. The specific radioactivities of free and esterified cholesterol, in the different plasma lipoproteins and in the major organs, were measured at various time spans after the introduction. The results revealed a different source of cholesterol in chylomicrons and VLDL discharged by the intestine: the chylomicrons would principally carry esterified cholesterol coming from the intestinal contents, while esterified cholesterol coming from the intestinal wall was found mainly in VLDL. The free cholesterol of these lipoproteins would initially have the same origin as esterified cholesterol but rapid free cholesterol exchanges would introduce precociously cholesterol coming from other structures. The results demonstrated the significant role of the intestine in cholesterol synthesis and revealed that of VLDL in the internal secretion of cholesterol by the intestine. Chylomicrons also appeared to play a significant role in this secretion, by way of exchanges between intestinal cells and chylomicrons in the process of formation. Finally, the results suggested the existence of esterified cholesterol transfers from HDL to lower density lipoproteins (chylomicrons, VLDL and possibly LDL).

ISSN:0250-6807    

DOI:10.1159/000176958

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

After a single ingestion of a diet containing 14C-cholesterol, cholesterol radioactivity in the stomachal and intestinal contents, in the different organs and in the very low density lipoproteins (VLDL) and chylomicrons was measured at different times during 2 days. Based on the results, a quantitative model of cholesterol absorption and of its release into the VLDL and chylomicrons has been elaborated. This model takes into account the different processes implied in the turnover of intestinal cholesterol and that of the entire organism. It constitutes a coherent whole (satisfactory simulations for the variables studied, suitable mass balances for each compartment and the absence of major contradictions with preexisting quantitative data). Once again the model demonstrates the important part played by the intestine in rat cholesterol system dynamics. It takes into account the existence of two related exogenous and endogenous cholesterol pools from which the cholesterol released by the intestine into the chylomicrons and VLDL originates. The results suggest the existence of an important esterified cholesterol uptake from other plasma lipoproteins by the chylomicrons.

ISSN:0250-6807    

DOI:10.1159/000176959

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

A study has been carried out to measure the transfer rate of esterified cholesterol from the HDL into the chylomicrons, as previously suggested. Rats were intravenously injected with cholesterol-labelled plasma or red cells. The specific activity of esterified cholesterol of HDL and chylomicrons was measured during 12 h following injection. Results were treated by compartmental analysis. The transfer rate was 0.21–0.22 h-1 with an uptake rate of chylomicrons by the liver of 8 h-1 (t½ 5 min). This represents a 0.8 mg h-1 flux of esterified cholesterol from HDL into chylomicrons, i.e., in our conditions, 75% of the total input into the chylomicrons esterified cholesterol. This process could be the major way for the disappearance of HDL esterified cholesterol.

ISSN:0250-6807    

DOI:10.1159/000176960

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

Studies were made in adult rats using an isotopic 15N method. Whole egg, wheat, casein and Viciafaba protein isolate served as reference proteins. The diets were isonitrogenous and feed intake was adjusted to the maintenance energy level. Variations in true N digestibility were small (91.8–96.1%). The amount of metabolic fecal nitrogen in animals receiving the diet containing wheat was 9.4 mg/l00 g body weight compared with 4.9–5.8 mg in the other diets. The differences in nutritional quality for maintenance between proteins of plant and animal origin were small. However, spinning (alkaline treatment) and additional cross-linking with aluminum ions or dialdehyde starch affected the nutritional quality for maintenance.

ISSN:0250-6807    

DOI:10.1159/000176961

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The influence of a supplement of linseed oil (LO), rich in linoleic acid (C18:3, n-3), was compared with one offish oil (MaxEPA) rich in eicosapentaenoic acid (C20:5, n-3) and docosahexaenoic acid (22:6, n-3) on blood and tissue lipids in weanling rats receiving a high intake of linoleic acid. Both the LO and the MaxEPA supplement decreased plasma cholesterol concentrations. The MaxEPA supplement but not the linseed oil supplement also decreased the concentrations of plasma triglycerides and HDL cholesterol. The proportion of C20:5, n-3 was markedly increased in the platelet and erythrocyte lipids by the MaxEPA supplement but not in tissue lipids. However, the increase in the proportion of C20:5, n-3 in the platelet was small compared with other studies. Both supplements led to an increase in the proportion of C22:6, n-3 in blood and tissue lipids but the MaxEPA supplement was more potent than the LO supplement. The most marked change was observed in the heart lipids. These changes were accompanied by reciprocal changes in the proportions of arachidonic, adrenic and docosapentaenoic acid.

ISSN:0250-6807    

DOI:10.1159/000176962

出版商:S. Karger AG    

年代:1985

数据来源: Karger