ISSN:0250-6807    

DOI:10.1159/000175616

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

Iron deficiency causes cytological and enzymic changes in the gastrointestinal mucosa of animals and man that can be expected to impair the digestion and absorption of other nutrients. In experiment 1, healthy, weanling, female rats were grouped into pair-mates and pair-fed either an iron-deficient or an iron-supplemented diet for 19 weeks. In experiment 2, iron-deficient offspring reared by iron-deficient females were grouped into pair-mates and pair-fed either an iron-deficient or an iron-supplemented diet for 15 weeks. In experiment 1, apparent absorption of calcium was significantly depressed in week 9 (p < 0.001) and slightly depressed in weeks 10 and 11. In experiment 2, the apparent absorption of calcium was significantly (p < 0.001) depressed in weeks 6, 13, and 14. Absorption was not measured in other weeks in these experiments. The concentrations of calcium and magnesium were consistently higher in the fecal dry matter of the iron deficient rats in both experiments. It was concluded that any defects in digestion and absorption by the iron-deficient rats was confined primarily to the mineral nutrients because in both experiments apparent absorption of dry matter was consistently higher in these animals compared to their iron-supplemented pair-mates.

ISSN:0250-6807    

DOI:10.1159/000175568

出版商:S. Karger AG    

年代:1975

数据来源: Karger

ISSN:0250-6807    

DOI:10.1159/000175619

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

The content of available sulphur amino acids in food proteins has been determined by the chemical methods after preliminary digestion of proteins with pancreatin. The values for the available methionine and cysteine contents of pure protein (casein, bovine serum albumin) and protein of food (fresh milk, whey, mackerel, beef, pork, wheat flour) estimated by the specific chemical methods were similar to those for the total content determined by the method of Moore et al. (6). Differences between total and available methionine and cysteine contents of heated casein were found.

ISSN:0250-6807    

DOI:10.1159/000175569

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

Human intestinal specificity toward sterols was studied by a balance method in 10 hyperlipoproteinemic patients fed plant sterol mixture with chromium sesquioxide as fecal flow marker. The mean fecal recovery of campesterol (C28) was 20 % less than that of β-sitosterol (C29). This difference persisted when corrected for fecal flow (by marker recovery), indicating differences in their intestinal uptake (C28 C29). The ratio of fecal cholesterol to its 5β-reduction products was lower than that of β-sitosterol in all patients; in vitro, 5β-reduction of both sterols was similar. The recovery of sterols from patients was unrelated to their 5β-reduction in the intestine. In sterol balance studies it is essential to measure cholesterol and plant sterols in the diet and to differentiate cholesterol and its transformation products from plant sterols and their products (Subbiah, 1972). Previous st

ISSN:0250-6807    

DOI:10.1159/000175570

出版商:S. Karger AG    

年代:1975

数据来源: Karger

ISSN:0250-6807    

DOI:10.1159/000175620

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

Young adult female rats were fed diets containing either 50 or 0 % lactalbumin at levels of 2, 4 or 6 g diet/day for 2, 8, and 16 days. There was no other protein in the diet. Tissue nitrogen and loss of radioactivity from tissues labeled with 14C- and 3H-glutamate were measured. In a second study, similar rats were fed graded levels of lactalbumin at food intake levels of 3, 5, or 7 g/day. Change in tissue nitrogen varied with the tissue, the time of observation, and the severity of the food restriction. After 8 days, animals fed high levels of protein at the most severe food restriction showed increases in gastrocnemius nitrogen and losses in liver nitrogen, while after 16 days both tissues had marked nitrogen losses. Nitrogen losses at the lowest level of food intake increased with the dietary protein level, whereas dietary protein was protective of tissue nitrogen at higher food intakes. Severity of energy restriction had no effect on loss of tissue radioactivity and the apparently longer tissue protein half-lives from animals fed protein-free diets are attributed to increased amino acid recycling. Such results indicate that short-term studies and overall nitrogen balance experiments will fail to identify changes occurring in different tissues and may yield misleading results.

ISSN:0250-6807    

DOI:10.1159/000175571

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

In an effort to better define some of the metabolic changes that accompany essential fatty acid deficiency (EFAD), we studied glucose metabolism in adipose tissue of EFAD and normal mice under basal conditions and in the presence of prostaglandin E1 (PGE1), epinephrine, and ACTH1-18. Isolated fat cells were incubated in Krebs-Ringer bicarbonate medium containing glucose 1–14C or 6–14C, and the incorporation of radioactive carbon into CO2 total fat, fatty acids, and glyceride-glycerol was determined. It was found that EFAD increased glucose uptake over controls which could be attributed to increased oxidation to CO2 and fatty acid synthesis. The contribution of the pentose cycle to glucose oxidation was 50–80 % higher in EFAD adipocytes as compared to controls. ACTH1-18g (0.1 μg/ml) suppressed this by 18 and 30 % in the control and EFAD groups, respectively, while epinephrine decreased pentose cycle activity by 83 and 55 % in the two groups, respectively. PGE1 alone had no significant effect, but in combination with epinephrine it abolished the inhibitory action of the catecholamine in both groups. It is suggested that, although EFA serve as prostaglandin precursors, the effects of EFAD on the metabolism of fat cells cannot be reversed by PGE1in vitro. However, these fat cells retain their responsiveness to the action of both lipolytic (ACTH and epinephrine) and antilipolytic (PGE1) agents.

ISSN:0250-6807    

DOI:10.1159/000175572

出版商:S. Karger AG    

年代:1975

数据来源: Karger

ISSN:0250-6807    

DOI:10.1159/000175621

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

Three groups of 24-day-old male Wistar rats were fed (a) a control diet containing 210 g/kg protein ad libitum (control) (b) a low protein diet consisting of the stock diet diluted with starch to contain 70 g/kg protein ad libitum (protein deficient) or (c) an amount of stock diet containing the same amount of protein as eaten by (b) but without starch (energy deficient). The low protein diet did not affect the ability of the animals to metabolize biphenyl and excrete it as 4-hydroxybiphenyl, or reduce the total activity of 4-hydroxylase per liver, whereas this was reduced by restricted amounts of the high protein diet. The low protein diet resulted in raised levels of corticosteroids in the plasma. It is concluded that the raised specific activity, and unchanged total amount of biphenyl 4-hydroxylase per liver of the low protein animals is an adaptation to the diet mediated by corticosteroids as exogenous corticosteroids were also found to increase the activity of this enzyme in normal animals.

ISSN:0250-6807    

DOI:10.1159/000175573

出版商:S. Karger AG    

年代:1975

数据来源: Karger