摘要:

The mechanisms of the fetal transmission of vitamin A were investigated by injecting 125I-retinol-binding protein (RBP), 131I-prealbumin and 3H-retinol-RBP in 9 pregnant rhesus monkeys. Samples of blood, amniotic fluid, and when needed fetal liver and kidney were collected after 2.5–48 h. 125I-RBP and 131I-prealbumin were detected in fetal plasma and amniotic fluid already in the first samplings. The specific radioactivity of fetal RBP increased during the first 25 h but never exceeded 13% of the maternal value. This is presumably due to concurrent synthesis of RBP (and prealbumin) by the fetus. The maximum specific activity of 125I-RBP in amniotic fluid was 70% of the maternal value indicating that the protein was predominantly derived from the mother. 3H-retinol was more readily transmitted to fetal plasma than RBP. A significant portion of the 3H activity was found in the lipoproteins suggesting that some retinol enters the fetal circulation by other routes than those involving transmission of RBP. The high specific activity of retinol in the fetal kidney implicates its direct involvement in the turnover of transmitted vitamin A. Quantitatively, however, the accumulation of vitamin A activity was largest in the fetal live

ISSN:0250-6807    

DOI:10.1159/000176840

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

The intake of a stable diet during 25 months by 68 women living in a closed religious community allowed us to study the effects of various alimentary fats on the serum lipids. Thus we could observe the consequences of the quantitatively and qualitatively different fatty acids in the diet, while the total quantity of lipids and the other constituents of the dietary intake were unaltered. The serum total cholesterol and apoprotein B levels are correlated with the P/S ratio of the diet; on the contrary, the serum HDL cholesterol and apoprotein A levels are not correlated with the fatty acid composition of the diet. The moderate supply in lipids (30% of the total caloric intake) and cholesterol (300 mg/day) maintained during this study corresponds to the usual dietary recommendations. Therefore, not very high levels of serum total cholesterol were observed, whichever vegetable oil was consumed.

ISSN:0250-6807    

DOI:10.1159/000176841

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

The effect of 2 % cholesterol feeding on changes throughout postnatal development of total, free, and esterifed cholesterol in neonatal chick liver and kidneys was studied. The increase observed in the hepatic cholesterol content after supplementation of the diet with 2% cholesterol was mainly due to the accumulation of esterifed cholesterol. Small but significant differences were also found in the esterifed cholesterol content in kidneys between control and cholesterol-fed animals. In normally fed chicks, the hepatic percentage of squalene synthesized from mevalonate decreased during the first days of independent life while cholesterol percentage increased. On the contrary, the percentage of squalene recovered in kidneys immediately after hatching was minimal, increasing during postnatal development. Addition of 2 % cholesterol to the diet produced a clear inhibition in the mevalonate incorporation into nonsaponifiable lipids by liver slices, especially from 4 days onwards. This inhibiion was particularly clear in the percentage of cholesterol synthesized. Mevalonate incorporation by kidney slices was higher than in liver, although cholesterol supplementation had little influence on the percentage of each nonsaponifiable lipid formed. In normally fed chicks, kidneys metabolized mevalonate by the shunt pathway not leading to sterols at a rate more than 50 times that of liver. Cholesterol feeding produced a clear enhancement of the hepatic shunt pathway while in kidneys it had practically no effect.

ISSN:0250-6807    

DOI:10.1159/000176842

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

In 8 healthy volunteers blood levels of branched-chain amino (BCAA) and keto acids (BCKA) were determined in response to a protein-rich meal. Serum concentrations of leucine, isoleucine, valine, α-ketoisocaproic acid and α-keto-β-methyl-n-valeric acid increased within 30 min and continued to rise throughout the observation. Only the keto analog of valine remained unaffected. As the BCAA increased significantly more percentagewise than their keto analogs, the ratios between amino and keto acids became augmented. It is suggested that (1) augmentation of keto acids may reflect transamination of amino acids rather than intestinal uptake; (2) the overall capacity of the organism for decarboxylation of ketovaline is greater than for the other keto acids, and (3) augmentation of the ratio between BCAA and BCKA may favor the storage of amino acids from the protein load into the body’s protein stores.

ISSN:0250-6807    

DOI:10.1159/000176843

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

The hexose monophosphate shunt (HMPS) pathway activities were measured in lung and liver by estimating the relative conversion of [1-14C]-glucose and [6–14C]-glucose into 14CO2 as well as by assaying the glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase activities. The HMPS activities were depressed in the livers of diabetic and hypophysectomized rats and enhanced by 3,5,3’-L-triidothyronine (T3) or insulin. The hepatic HMPS activities were stimulated to supranormal levels when normal rats were injected with T3. T3-mediated stimulation of hepatic enzyme activities was dependent on the dose and duration of the hormonal treatment. Half-lives of T3-induced synthesis and degradation of glucose 6-phosphate dehydrogenase were 20 and 96 h, respectively, and of 6-phospho-gluconate dehydrogenase were 19 and 90 h, respectively. Although HMPS activity was found in lung, the activities of the HMPS pathway dehydrogenase did not vary with the alteration of hormonal conditions, nor the activities were stimulated by the action of T3 or insu

ISSN:0250-6807    

DOI:10.1159/000176844

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Electron microscopy of hepatic cells from protein-deficient young rats revealed extensive breakdown of the rough endoplasmic reticulum into fragments and vesicles whose membranes appeared fully studded with ribosomes. Additionally, there was biochemical evidence of marked disaggregation of polysomes (n > 2), and this was more prominent in the membrane-bound than in free polysomes. Protein malnutrition increased the proportion of membrane-bound ribosomes which were salt-releasable and therefore temporarily non-functional. It has been concluded that disaggregation of membrane-bound polysomes induced by malnutrition does not necessarily imply detachment of the monomeric ribosomes from the endoplasmic membrane into the pool of free ribosomes, which probably has a separate polyribosomal cycle.

ISSN:0250-6807    

DOI:10.1159/000176846

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Moderate alcohol consumption is associated with lower cardiovascular mortality. The effect of moderate alcohol intake during 5 weeks on lipoproteins, especially on the high density lipoprotein (HDL) cholesterol total (of which the levels are inversely predictive of coronary heart disease) and apoproteins A, A1 and B, was studied in 7 normal men. HDL cholesterol total appreciated by the heparin manganese precipitation method and phosphortungstate magnesium method increased (p < 0.01) during alcohol consumption. The composition of HDL was modified by alcohol consumption: increase of the esterified/total cholesterol ratio (p < 0.05) and phospholipids (p < 0.05) without significant modification of triglycerides. Low density lipoprotein and very low density lipoprotein did not vary significantly. Apoprotein A1 increased during alcohol consumption (p < 0.05) with a transitory increase of apoprotein A. There was no significant modification of apoprotein B.

ISSN:0250-6807    

DOI:10.1159/000176849

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

In a total of 22 healthy women, the concentrations of vitamin A, retinol-binding protein (RBP), β-carotene, vitamin E, pyridoxal-5’-phosphate (PLP), folic acid, vitamin B12, biotin and vitamin C as well as the activities of the erythrocytic enzymes, erythrocyte transke-tolase (ETK), erythrocyte glutathione reductase (EGR) and erythrocyte glutamate oxalacetate transaminase (EGOT) were measured and compared at delivery, 3-5 days post-partum (pp) and 5-10 weeks pp. The mean values indicated a post-partal increase of vitamin A, RBP and vitamins B12 and C; and a post-partal decrease of PLP, folic acid, biotin, vitamin E and β-carotene. The basal activities ETK0 rose at the end of puerperium above the values measured at delivery, while EGOT0 were lower than at parturition. None of the women had an adequate biochemical vitamin status for all vitamins measured over all three investigations. The biochemical vitamin deficiency of biotin was found most often, followed by vitamins B12, B6, C, A, fòlic acid, B2, B1 and β-carotene; vitamin E status was optimal in all

ISSN:0250-6807    

DOI:10.1159/000176851

出版商:S. Karger AG    

年代:1984

数据来源: Karger

ISSN:0250-6807    

DOI:10.1159/000176854

出版商:S. Karger AG    

年代:1984

数据来源: Karger

ISSN:0250-6807    

DOI:10.1159/000176856

出版商:S. Karger AG    

年代:1984

数据来源: Karger