The effect of graded doses of erythorbic acid (ErA) on the content of ascorbic acid (AsA) in the tissues of guinea pigs administered AsA was studied. The guinea pigs were administered 5mg AsA and 1, 5, 20, and 100mg ErA; or 1 mg AsA and 1 and 20mg ErA; or 20mg AsA and 20mg ErA for 16 days. The animals were then sacrificed, and the liver, adrenal glands, spleen, and kidneys were removedd to determine the contents of AsA and ErA by using HPLC. The content of AsA in the tissues of the animals administered less than 5mg ErA together with 5 mg AsA was not significantly different from that of the animals administered 5mg AsA. The administration of 100mg ErA together with 5 mg AsA caused a decrease in the amount of AsA in the tissues. The content of AsA in the tissues of the animals administered ErA together with 1 mg AsA was not significantly different from that of the animals administered 1mg AsA. In the case of animals administered an equal amount of both AsA and ErA, the AsA tissue content was consistently much higher than that of ErA. These results indicated that the administration of relatively small amounts of ErA did not appear to reduce the availability of AsA.

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The effects of fructose (F), a glycogen precursor, and arginine (A), a stimulator of insulin secretion, on glycogen stores in liver and skeletal muscle and lipolysis were studied in endurance exercising rats, in comparison with that of glucose (G) and A. The addition of citrate (C), which previously has been shown to stimulate liver and muscle glycogen repletion after exhaustive exercise, was also tested. Rats were meal-fed twice daily and underwent treadmill running 6 days a week for 3 weeks (experiment 1) or treadmill running for 3 days and the usual voluntary wheel running of 3 days a week for 5 weeks (experiment 2). On the final days of experiments, rats were given one of the following water solutions; a 3.3g F+0.5g A per kg bw, a 3.3g G+0.5g A per kg bw and water (experiment 1) and a 3.3g F+0.5g A+0.5g C per kg bw (experiment 2), at the 1.5h point during a 3h treadmill running course at 26 and 32.5m/min up a7° incline, respectively. There was a significant reduction in liver and soleus muscle glycogen during the period of exercise. The administration of either F+A or G+A during exercise was useful in preventing the further depletion of liver and muscle glycogen stores. The administration of G+A significantly suppressed an increased adipose tissue lipolysis caused by exercise, when compared with that of either F+A or water (experiment 1). The addition of C to F+A appeared to spare more soleus and liver glycogen stores during exercise, when com-pared with G+A (experiment 2).

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Influences of indigestible dietary bulk (kaolin), short chain fatty acids (SCFA), and their interaction on the weight and epithelial cell proliferation rate of digestive organs were studied. Rats with an ileal fistula were fed an elemental diet with or without kaolin (10% w/w). They were given a 3 ml SCFA mixture (acetate, propionate, and butyrate; 100, 20, and 60mM, respectively; pH 6.1) or a 3ml NaCl solution (180mM; pH 6.1) via the fistula twice a day for 14 days. Kaolin, but not SOFA, increased full and empty body weight by 14% and 13%, respectively. Kaolin increased the tissue weight, but not relative tissue weight (tissue weight/empty body weight), of the forestomach, distal colon, liver and heart by 6-14%. SCFA, independent of the presence of kaolin, increased the weight and the relative weight of the cecum, both by 15%. SCFA, but not kaolin, increased the cryptal cell production rate in colonic segments by 50-140%. These results indicate that (a) SCFA accelerates epithelial cell proliferation, thereby increasing cecal tissue weight, (b) kaolin stimu-lates body weight gain which is accompanied by a proportional increase in the tissue weight of some digestive organs, and (c) the actions of these factors are independent of each other.

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The dietary intake of cholesterol, phytosterol and PUFA in Japanese was investigated to obtain information on dietary parameters related to coronary artery disease. Three daily menus for both 1957 and 1982 were prepared based on the daily per capita consumption of foods and nutrient intakes from national surveys. From 1957 to 1982, the average daily intake of cholesterol rose 2.1-fold from 183 to 376mg while that of phytosterol remained at about 373mg. Daily intakes of total fatty acid (19.2g), PUFA (7.3g), MUFA (5.8g) and SFA (6.1g) in 1957 increased in 1982 to 48.7g, 11.9g, 19.5g and 17.3g, respectively. The ratio of PUFA/SFA decreased to 56% from 1.23 in 1957 to 0.69 in 1982 and the PUFA/MUFA ratio also decreased to 48%. The PUFA/cholesterol ratio was lower in 1982 (31.8) than in 1957 (42.6), and the decrease in the phytosterol/cholesterol ratio to 46% was greater than that in the PUFA/cholesterol ratio (which only fell to 75% of the 1957 value). Thus, comparison of the 1982 and 1957 intakes indicated the increase in risk factors, cholesterol and SFA intake, and the decrease in the ratio of PUFA/SFA in the Japanese population during the past few decades.

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Growing rats were fed ad libitum soy protein isolate (SPI) or its peptic (SPI-P) or tryptic digest (SPI-T) for a month and their sera were examined for cholesterol and triglyceride levels and enzyme activities such as cholinesterase, glutamate-pyruvate transaminase (GPT) and alkaline phosphatase. The rats fed SPI-P or SPI-T were inferior in growth to those fed SPI. Similarly, the serum glyceride level was lower in the SPI-P and SPI-T groups than in the SPI group. On the other hand, a significant difference was found in the serum cholesterol level between the SPI-P and SPI or SPI-T groups but not between the SPI and SPI-T groups. A similar tendency was observed for serum GPT and alkaline phosphatase activities, although there were no significant differences among dietary groups in small intestinal enzyme activities. As for the atherogenic index being a risk factor inducing atherosclerosis, the order of its value was SPI-P<SPI<SPI-T.

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Age-related changes in nitrogen balance and related vari-ables in later life of male Wistar rats fed 14.0g/day (group C) or 8.7g/day (group R) of 20% casein diet throughout life were examined at intervals of 50 days from day 650 of age. In both groups, body weight decreased from about day 600, and the body weight at the final examinations (on day 1, 000 in group C and 1, 100 in group R) were 18% and 13%, respectively, less than those on day 600, although the animals consumed more than 98% of their food throughout. Their nitrogen balance fluctuated through-out later life in both groups, but the overall changes did not show a consistent negative or positive pattern. Consequently, the mean nitrogen balance after 650 days of age was calculated as -11.5±45.3mg N/day in group C and-1.3±11.6mg N/day in group R. On the other hand, protein digestibility increased steadily after 650 days of age in both groups. As a whole, nitrogen metabolism at the whole body level did not change consistently even in later life.

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6-O-Palmitoyl-AsA (AP) and -DHA (DHAP) suppressed LA peroxidation considerably in both 10% and 20% EtOH solutions. The duration of the suppression of LA peroxidation was longer with AP than with DHAP. But after the initial suppression of LA peroxidation, both derivatives showed an accelerating effect. 6-O-Acetyl-AsA (Ac-AsA) and -DHA (Ac-DHA) accelerated LA peroxidation from the start of the reaction in 10% EtOH, but suppressed it notably in 20% EtOH. 4-Phenyl-2, 3-dihydroxy-2-buten-4-olide (PDHB) and 4-phenyl-2, 3-dioxo-4-bute-nolide (PDOB) accelerated LA peroxidation in 10% EtOH. With 20% EtOH solution, PDHB suppressed LA peroxidation notably, as did AP, but PDOB showed only a short duration (about 1h) of suppression. These results suggest the complexity of LA peroxidation catalyzed by lipophilic AsA or DHA in aqueous solution containing alcohol.

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The growth pattern of visceral organs was investigated in monosodium L-glutamate (MSG)-treated obese mice with hypothalamic lesions. Male Jcl-ICR strain mice were subcutaneously injected with MSG, 2mg/g of body weight daily, for five days after birth. The MSG-treated mice became obese after 4 weeks of age.
According to patterns of weight gain compared with those in the control mice, the visceral organs in the MSG-treated mice were classified into three groups as follows: The first group of organs (heart, lungs, spleen, pancreas, kidneys, testes, brain and submandibular glands) remained absolutely lower in weight throughout their growth. The second group of organs (liver and stomach) was low in weight until 12 weeks of age, but became identical to that of the control mice after 16 weeks of age. The third group of organs (epididymal fat, small intestine and colon) showed lower weight until 4 weeks of age and were significantly heavier than those in the control mice after 8 weeks of age.
The heart in the first group of organs apparently had hypertrophic muscle cells after 8 weeks of age and became significantly hypoplastic due to decreased cell production as was revealed by the continuous suppression of mitotic activity and DNA synthesis by [³H]thymidine autoradiography. The liver in the second group of organs became significantly hypoplastic due to decreased cell production and showed the same weight with the control mice due to the development of fatty liver. The small intestine in the third group of organs became hypoplastic due to decreased cell production in the crypts until 4 weeks of age, and became hypertrophic and hyperplastic by the acceleration of cell production in the crypts from 4 to 8 weeks of age.
From these findings, in the MSG-treated mice with specific growth patterns of visceral organs, it is suggested that low energy expenditure results in a relatively excessive energy supply and leads to obesity, because most of the important organs with major physiological functions became hypoplastic. Moreover, it seems that hypertrophy and hyperplasia of the intestine suggest a possible acceleration of the absorptive function.

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The effects of dietary sulfur-containing amino acids and glycine on plasma cholesterol level were studied in rats fed amino acid mixture diets containing cholesterol. The relationship between the amino acid composition of dietary proteins and plasma cholesterol levels was also investigated in rats fed diets containing various kinds of protein such as casein, egg albumin, pork protein, fish protein, corn gluten, wheat gluten and soy protein. Feeding the amino acid mixture corresponding to casein led to an approximately two-fold level of plasma total cholesterol as compared with feeding the amino acid mixture corresponding to wheat gluten. It was possible to reduce the plasma cholesterol of rats fed the amino acid mixture of the casein type by increasing the proportion of cystine in the total sulfur amino acids. Inversely, the deprivation of cystine resulted in an enhancement of the plasma cholesterol of rats fed the gluten type amino acid mixture. Glycine had a tendency to resist increases in the plasma cholesterol level. A significant negative correlation was noted between plasma cholesterol levels and the content of cystine in intact dietary proteins. The results suggest that the differential effect of dietary proteins on plasma cholesterol level is mainly associated with sulfur-containing amino acids included in the protein, regardless of whether it is of animal or plant origin.

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The main objective of the present work was to study the interference of rat endogenous nitrogen excretion with the assessment of digestibility and biological value of dry bean (Phaseolus vulgaris, L.) protein. Dry bean plants were cultivated under (¹⁵NH₄)₂SO₄ fertilization and at harvest dry beans had 1.080 atoms % of ¹⁵N-excess. Nitrogen balance studies indicated that bean protein digestibility and biological value were higher when N-balance was based on ¹⁵N-excess as compared to total nitrogen, both for undenaturated and heat-denaturated protein. The ¹⁵N-balance also showed that heat treatment significantly improved (p≤0.05) the digestibility of bean protein in the integral flour and in protein isolate while the biological value decreased for both materials. The results permitted the conclusion that the conventional methods employed for calculation of bean protein digestibility and biological value, based on total nitrogen balance and protein-free diet, underestimate these indices of protein quality.

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The long-term and short-term influence of large oral doses of ascorbic acid on the urinary excretion of calcium has been investigated. In the first experiment, daily doses of a total of 10g of ascorbic acid were administered to healthy human subjects. Daily urinary samples of these subjects were collected before and during the treatment, and calcium contents of these samples were measured. Among the 22 subjects, 19 experienced no significant changes in urinary calcium levels during the ingestion of ascorbic acid, one subject experienced an increase, two had a decline. These changes in urinary calcium levels were relatively small and were within the changes from consuming normal diets.
In the second experiment, urinary samples of 46 healthy subjects were collected during a period of 8 hours after the ingestion of 2g of ascorbic acid (33 times the U.S. RDA). A significant increase in mean urinary calcium excretion from 48.2±25.1mg to 58.3±28.0mg in the 8-h time period was observed. Mean urinary volume and phosphorus were unchanged. Calcium levels of the initially low excretors were significantly elevated while the change in urinary calcium levels of the initially high excretors was not statistically significant following the administration of ascorbic acid. The results suggest that ascorbic acid has a short-term effect on the regulation of the absorption and metabolism of calcium in humans.

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