The cytogenetic effects of short-term zinc deficiency on bone marrow cells and unfertilized oocytes were studied in rodents. Simultaneously, the susceptibility to mutagens in the zinc-deficient state was examined in vivo.

Male mice were given control or zinc-deficient diet for 4 weeks. The incidence of sister chromatid exchanges (SCE) of bone marrow cells in zinc-deficient mice was 11. 4±1.0, which was different from 6.9±1.7 in control mice. There was a dose response with respect to SCE frequencies in the mitomycin C (MMC) -treated groups. The MMC-induced SCE were additively increased in zinc-deficient mice. However, no differences in mitotic chromosome aberrations and cell cycle kinetics were not found among groups. There may be a fundamental relationship between the induction of SCE and the disturbed zinc metabolism.

In female hamsters given zinc-deficient diet for 8 days (2 estrous cycles), the mean number of ovulated oocytes (11.6±1.6) was decreased significantly compared with 14.1±1.6 for the controls. However, no apparent increases of degenerated oocytes and meiotic chromosome aberrations were encountered in both hamsters. The increase in diploid oocytes was the most prominent effect in cadmium-treated hamsters. However, there was no difference in the incidence of diploid oocytes between control and zinc-deficient hamsters. These findings indicate a possible inhibitory effect of zinc deficiency on ovulation.

When rats are offered a zinc-deficient diet, they decrease their total food intake. Their normal food intake alternate with low intake in a 3-5 day cycle. The present study was conducted to examine the function of free zinc in the regulation of appetite in zinc-deficient rats.

Zero, 1. 5, 15 and 150 ppm-Zn as Zn (NO₃)₂ and 150 ppm-Zn as ZnSO₄ dissolved in 10 μl of Ringer solution was injected into the lateral ventricle of zinc-deficient rats indicating low food intake. The central administration of Zn was once a day at 8:00 p.m. The daily food intake was measured during short (3 days) and long (8-11 days) period of the injection. Total food intake and the cyclic alternation of daily food intake in zinc-deficient rats were not recovered by the lateral-ventricular administration of inorganic Zn. The reduced food intake by dietary zinc insufficiency may not depend on the change of extracellular zinc concentration.

Zinc deficiency induced several brain lesions such as disturbances and defects of memory, learning and olfactory acuity. In this study, the relationship between these zinc deficiency-induced brain lesions and movement of trace elements in the brain was examined.

Zinc deficiency induced significant accumulations of iron and aluminum into the hippocampus. Further, aluminum-dust exposure through the nasal mucous membrane under the manifestation of zinc deficiency induced an extreme depletion of iron and an excessive accumulation in the hippocampus. These phenomena were similarly observed in the olfactory bulb.

These results showed that zinc deficiency might induce a breakdown of defense systems against aluminum invation with the development of olfactory lesion. Consequently, aluminum might be easily transported to the hippocampus through the olfactory systems such as the nasal mucous membrane and olfactory bulb. Further, these results suggest that there is a competitive reaction between iron and aluminum and that this competition includes a participation of binding substances of iron or aluminum such as transferrin and ferritin.

Borep peptide (B) (made from the globin protein of bovine red blood cell) and whey peptide (W) (made from whey protein) have been reported about the function to regulate the fat metabolism. Borep (B) improved the serum tria:cylglycerol and whey peptide (W) depressed the serum total cholesterol.

Taurine in the oyster extract (O) improve the cholesterol metabolism in serum and liver.

We have studied about the influence of the oligopeptide (B and W) and oyster extract (O) on the lipid metabolism in rats. Normal diet and high fat diet were fed to 2 groups of Wistar male rats. After 4 weeks, the diet of high fat diet group was changed to normal diet (HC group). We added the Borep (B), whey peptide (W) and oyster extract (O) with various combinations to HC diet, i.e. HC, HC+O, HC+B, HC+W, HC+O+B and HC+O+B+W groups. After breeding each group for 4 weeks, we took the serum and analyzed the total cholesterol and triacylglycerol of them.

Comparing with HC group, total Cholesterol (TC) of the HC+W group was slightly decreased and triacylglycerol (TG) of the HC+B group was also slightly decreased in the carotid and peripheral serum. But carotid serum TG of HC+O group significantly decreased, though peripheral serum TC of HC+O slightly decreased. In the liver of HC+O group, TC and TG decreased. Comparing the HC+B group, TC and TG in the carotid and peripheral serum slightly decreased. And in the HC+O+B+W group, carotid TG decreased compared with other groups.

Lipids of oyster contain available components such as eicosapentaenoic acid and docosahexaenoic acid. But, phospholipids and chlorophyll derivatives are also extracted by n-hexan method. Lipids of oyster extracted by this method are easily oxidized and polymerized. So we could not use them easily.

But lipid extract by supercritical carbon dioxide method (S.C.E.) is known to be not oxidized and polymerized.

S.C.E. does not extract the polar lipids such as triacylglycerol, carbohydrate and free fatty acids. S.C.E. is the safe extraction method, because the S.C.E. extraction does not contain chlorophyll and chlorophyll derivatives, and also the extraction solvent (carbon dioxide) is easily removed from the extract compared with n-hexan method.

We have studied about the utilization of S.C.E. in the extraction of oyster lipids. And we analyzed the lipids components to compare the both extraction methods.

Euglena gracilis Z grown under light is rich in sulfur-containing lipid, sulfoquinovosyldiglyceride (SQDG). However, the cells grown in the dark and its bleached mutant strain, SMZ that lacks chloroplasts does not accumulate as high SQDG content as E. gracilis Z grown under light. E. gracilis Z as a model of plant cell and E. gracilis SMZ as a model of animal tell were used to examine how they respond to UV-B irradiation stress. Only light-adapted E. gracilis Z was found to keep intracellular hydroperoxides level low even under UV-B exposure. We compared the antioxidative effect of SQDG and taurine both of which have common chemical structure as sulfonate group. Model experiments were made with water soluble initiator, 2,2’-azo-bis-(2-amidinopropane) dihydrochloride [AAPH] or UV-B irradiation with a peak at 312 nm in the presence of 3-hydroxykynurenine by using SQDG-embedded multilamellar liposomes or taurine-added liposome. Results showed that both in liposomes containing SQDG or taurine, AAPH-induced lipid peroxidation was significantly inhibited, but UV-B-induced lipid peroxidation was promoted in the SQDG-containing liposomes. Any significant effect was not recognized in the taurine-containing liposomes. Methylated SQDG also showed the same results as native SQDG, which suggest sulfonate group seems to have something to do with radical scavenging. In chloroplast, SQDG may play as a synergistic role for other antioxidants to prevent peroxidative damage in the light-adapted E. gracilis Z.

Aluminum (Al) is the third most abundant element in the earth’s crust, but the behavior of Al in human and other animals are still unknown. In this study, we investigated whether Al is incorporated in organs of experimental animals receiving Al compounds. Al was given to animals in the form of ion (Al³⁺) or its complex (aluminum-maltolate) . We used aluminum chloride (AlCl₃・6H₂O)in saline solution as aluminum ion and gave it to rats at the age of 5 and 13 weeks by intraperitoneal injection at a dose of 10 mg Al/kg body weight for 5 days. On the other hand, we used aluminum maltolate (AlM) as an aluminum complex, which was given to mice aged of 6 weeks by oral administration or free access to tap water containing AlM for 90 days. Organ distributions of both Al compounds exhibited similar tendency. Al was mainly accumulated in the liver and spleen. Especially, Al levels of the spleen and liver of animals receiving AlCl₃ were significantly higher than those of control animals. But in the kidney no significant difference in Al accumulation was observed. We also found that Al accumulated in the brain domain of young rats who received AlCl₃ injection and mice who received daily oral AlM or free access of drinking water containing AlM for a long-term. These results will be important to elucidate the physiological role of Al, in terms of the development of neurological diseases like Alzheimer’s disease.

Dialkyltin compounds such as dibutyltin and dioctyltin induce a severe thymus atrophy and a concurrent cellular immunodeficiency. However, this atrophy is recovered by a long-term exposure (5 ~ 8 weeks), that is, a tolerance for the dibutyltin-induced thymus atrophy has become apparent. This tolerance is not due to inducing the generation of degradation enzyme working in the dealkylation of organotins. Rather it appears to be caused by inducing the generation of a dibutyltin-binding substance or an unknown substance which is capable of preventing the dibutyltin-induced suppressive effects, specifically, antiproliferation and death of the thymocytes.

Deficiencies and excesses of trace elements induce various kinds of brain lesion. In this study, a tributyltin-induced olfactory lesion (anosmia) was examined by the kinetic analysis of the mechanisms in an excessive accumulation of calcium into the olfactory bulb, an inhibition of olfactory signal transduction and toxic cell death (necrosis or apoptosis).

The trialkyltin-induced excessive increase of calcium in the olfactory bulb was associated with an increase of olfactory PTH. Since the IP₃ level in the olfactory significantly decreased under the tributyltin exposure, which seems to be a consequence of tributyltin-induced inhibition of PI turnover, the excessive increase of olfactory calcium was not due to an influx of Ca²⁺ mediated by a plasma membrane IP₃-gated Ca²⁺ channel and a release of intracellular Ca²⁺ mediated by IP₃ receptor-channel complex from endoplasmic reticulum. The tributyltin-induced excessive increase of olfactory calcium is perhaps caused by an excessive increase in the formation of cAMP mediated by activation of adenyl cyclase and an excessive influx of extracellular Ca²⁺ mediated by cAMP-activated channels. Moreover, this rapid and excessive increase in the concentration of intracellular Ca²⁺ seems to inhibit CaM kinase II functions leading to necrosis in vivo or toxic cell death in vitro.

To investigate whether cili extract affects calcium absorption, 3-week old male Wistar rats were fed a diet containing 4. 5% cili extract or a control diet. At 23days after the initiation of feeding trial, the animals were subjected to 5-clays balance study. At 28days, plasma, small intestine and femur were collected. Transepithelial calcium transport of rats fed cili extract was examined using the everted gut sac procedure. Cili extract was considered to promote calcium transport in the upper small intestine and to affect the saturable pathway. Longitudial growth of femur was significantly (P<0.01) suppressed by cili extract, while specific gravity, density and calcium content were significantly (P<0.05) increased. On the other hand, plasma calcitonin, bone turnover indices ie. tartrate-resistant acid phosphatase and alkaline phosphatase in femur were not changed by cili extract. These actions of cili extract were similar to those of phytoestrogen.

Ultrasound bone densitometry of os calcis was performed on a sample of three-hundred and eighty-four healthy female students. From the results, they were separated into two groups from the original samples: Group 1 (62 subjects) having over the mean stiffness value lSD+ and Group 2 (57 subjects) under the mean stiffness value lSD-.

Next, we studied the following aspects of the two groups: 1) bone mineral density of the lumber vertebrae (L₂-L₄) by dual energy X-ray absorptiometry method, 2) serum calcium and alkaliphosphatase (ALP), 3) physical characteristics (height, weight, lean body mass; LBM, %Fat), 4) calcium intake from the milk and the milk products per day.

Results were as follows: Positive correlations existed between height and the serum ALP (r = 0.350, p<0.05), and the serum calcium and the ALP (r = 0.353, p<0.05) in the Group 1. Moreover, in the group of mean stiffness value 2SD+, there was also a positive correlation between the serum calcium and the ALP (r =0.697, p<0.05). Each physical characteristic had a positive correlation to stiffness, and weight and LBM showed especially high correlation efficients.

The above mentioned results may lead the following conclusions; Taller subjects show a higher rate of bone metabolism as do those with higher levels of serum calcium. However, this is only the case with students whose bones are well developed. Heavier subjects have a higher degree of stiffness and this increases with physical development.

The effects of dietary supplements of Sodium chloride (8g/100g diet) and voluntary running exercise on bone metabolism were studied in rats fed low calcium diet (0. 012% diet) Sodium chloride supplement significantly reduced weight gain. The mean weight of kidney were significantly increased by intake of Sodium chloride. The mean weight of femur and humerus were significantly lower in the group consuming a low calcium diet. The Sodium chloride supplemented rats exhibited a five-to seven fold increase in urinary calcium excretion, so calcium retention in those groups lost its balauce. There were no differences in breaking force of femur between the groups consuming a low calcium diet and control. However, the breaking force of femur in the group that exercised was significantly lower than that in the sedentary group of the low calcium diet. It is suggested that the low calcium intake restricts the bone formation though voluntary exercise rises bone turnover. The results of this study indicate that dietary Sodium chloride mediate bone loss and that sufficient calcium should be supplied during exercise.

Zinc deficiency associated with iron deficiency anemia was first recorded by Prasad in 1961. The precise role of zinc in the hematological abnormalities in man is not certain. Endurance runner have been known to suffered from anemia that simulated iron deficiency anemia. We conducted iron loading test to divide iron deficiency anemia (A group n=10)from zinc deficiency anemia (B group n=4). Age and athlete duration in group A and B were 18. 6±1.3 years and 22 .1±2.2 years, and 2.1±0.4 years and 7.1 ± 5.2 years, respectively. RBC, Hemoglobin (g/ dl) and MCV (fl) in group A and B were 480±30and 350±13, 9.2±1.8 and 9.8±1.0,and 19.2±2.9 and 23.6±2.23, respectively. Thus, zinc status might partly accounted for hematological abnormality in female endurance runner.

We examined the effect of strenuous exercise on blood constituent. Studies were made on healthy 13 members (19 ~ 27 years) of the canoe club of Kansai Medical University who participated in summer training camp for 15 days. Blood samples were drawn from an antecubital vein before and after training camp. After training camp, total protein, albumin and total cholesterol were significantly decreased, and total electrolyte (Na + K + Ca)were not affected. Serum GOT and GPT activities were not change but LDH and CPK activities were significantly increased. Hb and Ht values were significantly decreased and serum Fe level showed a tendency to decreased. Serum Zn level were significantly decreased but Se and Cu level were not changed. Serum antioxidative substance (ascorbic acid and α-tocopherol) levels were significantly decreased, while lipid peroxide level (malondialdehyde) was significantly increased. These data suggest that strenuous exercise can result in a reduction of nutritional status and an induction of oxidative damage.

Cells respond to metabolic perturbations by inducing specific stress proteins. Exposure of mammalian cells to oxidative stress induces heme oxygenase, the rate-limiting enzyme in heme degradation. The induction of heme oxygenase-1 has been hypothesized to represent a cellular antioxidant defense mechanism. The objectives of this study were to characterize the interaction of minerals in human intestinal epithelial cells (Caco-2 cell line) and to explain the mechanism of heme oxygenase-1 induction by oxidative stress. The induction levels of heme oxygenase-1 depended on chemical forms of iron (hemin > Fe (II) > Fe (III) NTA) in Caco-2. As opposed to hemin, Cu (II) is a weak inducer of heme oxygenase-1. Induction levels of heme oxygenase-1 when Cu (II) coexisted with hemin in the medium was same as when hemin only existed. Although both hemin and arsenate are strong inducers of heme oxygenase-1, the induction level of heme oxygenase-1 when arsenate coexisted with hemin was lower than when hemin or arsenate solely existed. These coexistences of minerals required a lot of time to induce a maximum level of heme oxygenase-1. Although it did not reveal whether generation of hydrogen peroxide by exposure to various minerals in Caco-2 cells initiated to induce heme oxygenase-1, it was demonstrated that hydrogen peroxide remarkably induced heme oxygenase-1. These results suggest dietary minerals affected the mechanism of heme oxygenase-1 induction in intestinal epithelial cells.

In our previous study it has been reported that either Ca or Mg in the "Function Water" prepared by the treatment with high electric field loading in the presence of charcoal or Al-Fe based ceramics should have participated in the restoration of regeneration of flagellum and motility of tributyl tin chloride (TBTCl) -intoxicatedEuglena gracilis Z. In the present study, the effect of "Function Water" prepared by Al-Fe based ceramics material on the ATPase activity of TBTCl-intoxicated E. gracilis Z was examined. The "Function Water" was prepared by immersing one piece of alumina-iron (Al-Fe) based ceramic in the ultra-pure water overnight before examining its effect. TBTCl-intoxication on the Euglena cells was brought about by exposing cells (10⁵ / ml) to 50 μM of TBTCl for 3 minutes. To examine restoration of motility of TBTCl-intoxicated cells by the "Function Water", the cells were washed and subsequently incubated with the "Function Water". Restoration of the cells was evaluated under the microscope equipped with computer aided image analyzer. Effect of "Function Water" on A TPase activity was evaluated by radio-assay using ³²P-labelled ATP and E. gracilis Z homogenate prepared from TBTCl-intoxicated Euglena cells or non-intoxicated cells.

Exposure of 50 μM TBTCl to Euglena cells for 3 minutes inhibited ATPase activity by ca. 40%, and incubation of the cells in Al-Fe ceramics treated water definitely recovered ATPase activity to 90% of the control activity in 4 hours. However, the "Function Water" which was treated with either EGT A or Chelex 100 to trap minerals did not show any restoration effect at all, indicating that minerals should have participated in its restoration. Since treatment with Desferal (deferoxamine) specific to iron cherating did not affect the restoration effect so much, the effect of the Al-Fe based ceramics treated water should not be due to iron but either Ca or Mg.

A main nutrient source for foals before the initiation of creepfeeding or weaning is mare’s milk. The epiphysitis in nursing foals has been frequently found in Hidaka district of Hokkaido Island. The incidence of the epiphysitis is thought to be due to rapid growth, imbalance of mineral intake, or deficiencies for Zn and Cu intake. The purpose of the present experiment is to clarify the intakes of trace minerals and nutritional status in mares and their suckling foals in Hidaka district.

Cu and Zn contents in milk were continuously decreased after parturition, which induced the lower intake of these minerals in their foals. Serum Cu concentrations were not changed after parturition in mares, and the levels were within a normal range.

Serum Cu concentrations were abnormally low in foals in 1 week after birth but recovered to the normal level in 3 weeks. Serum Zn concentrations were lower than the normal level in mares and their foals through the experimental period. These results suggested that mares and foals became Zn deficiency in this area. Zn deficiency induced by low Zn concentration in milk might cause the epiphysitis of foals.

Selenium, an essential trace element for mammals, birds, fishes, amphibia and some bacteria, shows various remarkable biological effects, and it is definitely required in various metabolic systems such as antioxidative defence systems, hormone regulated biosynthesis, constituents of muscle and anaerobic redox catalysis. The biological significance of selenium may be related to the unique functions of various selenoproteins which contain a selenocysteine residue as an integral part of their active site. Glutathione peroxidase is one of the most extensively studied selenoenzymes, and its catalysis is closely related to the antioxidative effects of selenium. However, glutathione peroxidase and other known selenoproteins such as iodothyronine 5’-deiodinase cannot explain all the biological effects of selenium. Discovery of a new selenoprotein would give us a significant insight for further understanding the physiological roles of selenium in human health. This article introduces protocol and skills frequently used in selenium biochemistry; the use of selenium-75 in detecting and identifying selenoenzymes, chemical identification of the selenocysteine residue, and precautions in selenoprotein purification.

Gangriosides compromise a family of acidic glycolipids that are characterized by the presence of sialic acid on the terminal carbohydrate portion. The localization of gangliosides is very high in a synapse membrane, amounting to 10% of total lipids in a nerve cell. In the neurotransmission system gangliosides may act together with neuroreceptor and interact with a neurotransmitter. It have been observed that a conformational change of gangliosides through acute or chronic administration of ethanol result in the degeneration of neurotransmission function. In this study, the effects of ascorbic acid deficiency, zinc deficiency and injection of ibotenic acid into olfactory bulb on the behavior of gangriosides at synapse in hippocampus were determined by HPLC and or in vivo micro dialysis technique with radioactive tracer. In the rat fed the ascorbic acid deficient diet for 3 weeks, the sialic acid originated from ganglioside (GSA) was decreased in hippocampus but no significant difference was observed in other parts of brain. In the rat fed the zinc deficient diet for 6 weeks, the sialic acid originated from sialoglycoconjugats (TSA) was decreased in hippocampus and striatum but no changes were observed for GSA. The amount of GSA in rat hippocampus under the effect of ibotenic acid injected (20 nmol) into olfactory bulb was increased on 4-day and recovered on 7-day. The sialic acid released from sialoconjugate on the synapse membrane of hippocampus by neuraminidase (30 mUmit) in vivo was 1.8 times more than that of control on 4-day.

It was clarified that the deficiency of trace nutrients effects on the amounts of gangriosides in central nerve system and on the function of neurotransmission.

In 1925, Matsuoka and Yoshimatsu reported about the new metabolite of Trp, which was named as kynurenin by Prof. Yashiro Kotake. And also the decomposed enzyme of kynurenin was named as kynureninase.

The Kynureninase is a B6 related enzyme, in which enzyme activity of the liver decreased in experimental DM rats.

In 1995, Takeuchi, Shibata et al. defined the primary structure of this enzyme protein, and its active center is similar to those of cystathionine synthase and lyase. Both decreased enzyme activity and diabetic conditions were recovered by taurine (intermedial metabolite of Met. or Cys) administration.

A blood group non-specific hemagglutinin which recognizes N-acetyl chitosaccharides was isolated from the homogenate of cherry tomato (Lycopersion esculentum var. Cherry), which showed the highest hemagglutinating activity among genetically diverse 28 kinds of tomatoes, by conventional ion exchange chromatographic techniques, and also by affinity chromatography on a chitin column. The purified cherry tomato lectin (LEcA) was a hydroxyproline-rich single polypeptide glycoprotein (Mr 100,000), containing 50% carbohydrate moiety (94% L-arabinose and 4% D-galactose)

The carbohydrate-binding specificity of the purified lectin was studied by quantitative precipitation and .hapten inhibition assay. This lectin was highly specific to β(1→4) -linked N-acetyl glucosaminyl units. It strongly reacted with N-acetyl-chitobiose-BSA, but not with N-acetyl glucosamine-BSA. The interaction of LEcA with thyroglobulin on GLISA (glycoprotein-lectin immunosorbe川 assay)was inhibited by N-acetyl-chitosaccharides, in order, [GlcNAc]₅ > [GlcNAc]₄ > [GlcNAc]₃ > [GlcNAch having approximately 194-times, 32-times and 5-times greater potency, respectively, than [GlcNAc]₂. The per iodate一oxidizedand reduced derivative of [GlcNAc]₄ and [GlcNAc]₅ were also good inhibitors, which showed similar inhibitory potency as the intact [GlcNAc]₂ and [GlcNAc]₃ respectively, strongly suggesting that LEcA recognizes internal N-acetyl-chitosaccharide sequence.

Although, LEcA showed non-inhibitory activity for sugar-hydrolytic enzymes from animal digestive tract, LEcA appeared to inhibit the active transport of sugar to some extent, on the epidermal membrane of rat small intestinal, as examined by using the everted sac. The histochemical study by immunostaining using anti-LEcA antibodies visualized the localization of the lectin on the rat brush-border membrane. This strongly suggested the cherry tomato lectin can bind to either the intestinal epidermal cell surface or the secreted glycoprotein which contain β(1→4) -linked N-acetyl-glucosaminyl sugar chains although it may not affect to the nutritional function.

The effects of 7-ketocholesterol on rat hepatocytes prepared by collagenase perfusion were examined. The addition of 7-ketocholesterol to the culture medium increased the relative ratio of total sterol to phospholipid of hepatocytes significantly in a time-dependent manner without changing the phospholipid content. And vitamin E suppressed the incorporation of 7-ketocholesterol into hepatocytes significantly. Although hepatocytes treated with 7-ketocholesterol produced a larger amount of O₂^-at the early stage of incubation than those treated with cholesterol, lipid peroxidation was not observed. When hepatocytes were treated with 7-ketocholesterol, vitamin E might prevent the hepatocytes from cell death not only by suppressing the incorporation of 7-ketocholesterol into hepatocytes but by scavenging O₂^-.

We first studied the effect of dietary protein concentration on immune responsiveness of C57BL/6 mice by measuring the proliferation response of splenocytes to mitogens. We used egg protein (PEP) as a protein source in diet, since PEP contains essential amino acids in good balance. The response of splenocytes to LPS, which is a B-cell specific mitogen, in mice fed on 2% protein diet was significantly lower than those in mice fed on each of 5% or 10% protein diet. While, the response of splenocytes to Con A, which is a T-cell specific mitogen, was unaffected by dietary protein restriction.

Next, we studied the effect of dietary protein type on immune responsiveness in relation to its sulfur amino acid concentration. The response of splenocytes to Con A in mice fed on 10% lactalbumin diet was significantly lower than those of mice fed on each of 10% soy protein (SPI), gluten, casein or PEP diet. The response to Con A of splenocytes in SPI and gluten diet groups were also slightly lower than those of casein and PEP diet groups. However, the response of splenocytes to LPS was unchanged by dietary protein type. In addition, the response of splenpcytes to Con A in SPI diet gruop was significantly increased by the supplement with L-methionine in the diet, which is a first limiting amino acid of SPI and casein. The response of splenocytes to Con A in casein diet group was・ also marginally increased, while, that of gluten diet group did not changed by L-methionine supplement. These results suggest that the immune response in T-cell may be in part controlled by the availability of sulfur amino acid from diet. However, the reason why the splenocytes in lactalbumin diet group shows low resposibility to Con A is uncertain.

Nitric oxide (NO) production from macrophages has been proposed to mediate the destruction of islet B-cells. Recently, we found that vanadium suppresses NO production from macrophages in STZ-induced diabetic mice. Then, we examined whether inorganic ions with insulin-mimetic activity such as Hg (II) , Cd (II) , Se (IV) , V (III) , V (IV) , Zn (II) and Mn (II) suppress NO production from macrophages. Dose-dependent inhibitory effects of these elements for NO production were observed, being in the following order: Hg (II) > Cd (II) > Se (IV) > V (III) > V (IV) > Zn (II) > Mn (II) .

To evaluate the insulin-mimetic activity of these ions, we examined the inhibitory effects of FFA release from adipocytes at the concentration of lmM of the ions. The inhibitory activity of FF A release from adipocytes was found to be in the order of Hg (II) > Cd (II) > Se (IV) > V (III) > V (IV) > Zn (II) > Mn (II) .

A correlation between inhibitory activity of FF A release and that of NO production was observed. This finding suggests that insulin-mimetic effects of these ions depend partially on the inhibition of NO production in adipocytes.

In the present study, we demonstrated the immunotoxic effects of organic arsenic compounds in marine animals, such as arsenosugar (AsSug) , arsenocholine (AsCho), arsenobetaine (AsBe) and tetramethylarsonium ion (TetMA) on murine principal immune effector cells, peritoneal macrophages (PMs) and alveolar macrophages (AMs) , comparing with the effects of inorganic arsenical, arsenite, in vitro.

Arsenite was strongly and equally toxic for both PMs and AMs, and the concentration of arsenite that decreased the number of surviving cells to 50% of that in untreated controls (IC₅₀) was 5 μM. Dimethyl arsenic compound in seaweed, AsSug, was weakly but significantly toxic only for AMs (IC₅₀ =8mM) and it actually enhanced viability of PMs to 1.5 times the control. In contrast, trimethyl and tetramethyl arsenic compounds in marine animals, AsCho, AsBe and TetMA, was less toxic even at the concentration over 10mM on both PMs and AMs.