Toshiyuki Tsukamoto

Relationship of cadmium accumulation to zinc or copper concentration in horse liver and kidney

The concentrations of Cd, Zn, Cu, and metallothionein (MT) in the liver, renal cortex, and renal medulla were determined in 24 male and 15 female younger thoroughbreds (age 27 to 97 months) and two old male horses (age 154 months and 190 months). High correlations were found between Zn and MT in the liver (partial correlation coefficient 0.836), between Cd and MT in the renal cortex (partial correlation coefficient 0.786), and between Cd and Zn in the renal cortex (partial correlation coefficient 0.675), while the correlation between Cd and MT in the liver was low (partial correlation coefficient 0.124). In the renal medulla, high correlations were found between Cd and Zn (partial correlation coefficient -0.631), between Zn and Cu (partial correlation coefficient 0.881), and between Cd and Cu (partial correlation coefficient 0.785). Therefore, in the liver, the MT concentration is the most highly correlated with the Zn concentration and is not correlated with the CD concentration unless artificially exposed to Cd. In the renal cortex, the MT and Cd concentrations are very highly correlated with each other. The Zn concentration is about 20 micrograms/g when the Cd concentration in the renal cortex is the lowest.

Studies on transitory laxative effects of sorbitol and maltitol: II: Differences in laxative effects among various foods containing the sweetening agents

Abstract We studied the laxative effect of sweetening agents, hydrogenated glucose syrup (HGS) containing 88–92% maltitol, and sorbitol contained in various foods. The subjects were 89 volunteers (64 males and 25 females). Foods used in the study were tablets, bevarages, chewing gum, jelly, adzuki-bean jelly, chocolate and candies which contained one of the two sweetening agents. The doses of the sweetening agents were 0.4 g/kg for sweets in tablet form and 20 g for the other foods. Approximately 10% of the subjects exhibited diarrhea after taking tablets as a control; approximately 20% did so after taking HGS except for adzuki-bean jelly; and approximately 30% did so after taking sorbitol. There was no significant difference between HGS and the control substance. The incidence of diarrhea tended to be higher with the two sweetening agents only when contained in adzuki-bean jelly. The length of time between the ingestion of test substances and the first onset of diarrheal stool varied widely from less than one hour to 23 hours among individuals. However, adzuki-bean jelly diarrhea was induced within 5 hours in all subjects. Soft stool accounted for 60 – 90% of the macroscopic findings of diarrheal stool. Chief complaints of abdominal symptoms were gurgling, flatus and lower abdominal pain.

Studies on transitory laxative effects of sorbitol and maltitol: III: Alterations in serum contents due to laxative effects

Abstract Maltitol or sorbitol was administered in doses of 0.8 g/kg to 20 physically healthy subjects (10 males and 10 females) and 6 diabetic patients (3 males and 3 females). Maltitol and sorbitol caused diarrhea in 75% and 95% of the subjects, respectively. Stool was watery in most of the subjects. The serum concentration of each sweetening agent was as low as approximately 0.3 mg/dl 2 hours after administration. The serum concentrations of Na, K, Cl, BUN, glucose and insulin did not change 2 hours after administration.

Effect of dietary protein on the distribution of cadmium, zinc and copper in rats following the oral administration of cadmium

Abstract Cadmium, 100 μg/rat/day, was administered orally 100 times (total amount of Cd administered, 10 mg), under conditions of low protein intake. The total amount of Cd in the liver and kidneys was as follows: females fed 20% protein diets > females fed 5% protein diets > males fed 20% protein diets ≒ males fed 5% protein diets. A decreased Zn concentration was found in the liver of males and the pancreas of males and females fed with the 5% protein diet. The Cu concentration in the kidneys was markedly influenced by low protein intake.

Effects of Cadmium on the Metal Distributions in Liver and Kidney and the Enzyme Activities in Serum under Inhibited Metallothionein Synthesis

MTはCd暴露に対して防御作用を有すると考えられている。本研究では,シクロヘキシミド(Cy)によりMT合成を抑制された場合,Cd暴露によって血清中酵素活性,肝,腎中Cd,Zn,Cu濃度ならびに肝,腎上清中の3金属の結合蛋白組成に如何なる影響を及ぼすかについて雌雄のマウスを用いて実験を行い,以下の結果を得た。1) Cy,Cdの同時投与により肝中MT濃度は,Cd単独投与群に比べて,雄30%,雌で19%に減少し,腎では雄で55%,雌で64%に減少した。2) Cy,Cdの同時投与により肝Cd濃度は,Cd単独投与群に比べて雌雄共に約85%に減少し,腎Cd濃度は雄で124%,雌で112%に増加した。3) 肝,腎中Zn,Cu濃度に対して,MT合成抑制による影響は認められなかった。4) 肝上清の蛋白結合Cdの組成は,Cd投与によりMT画分に雄75%,雌82%存在したが,Cy,Cdの同時投与により,雄45%,雌28%に減少し,高分子量画分のCd割合が増加した。腎のホモゲナイズ上清では,Cd投与群においても大部分が高分子量蛋白に結合していたため,MT合成抑制によるMT画分のCdの減少は著変を示さなかった。5) 肝,腎上清の蛋白結合Znは,対照群,Cd投与群共に,すべてMTより高分子量蛋白に結合して存在しているため,MT合成抑制による影響は認められなかった。6) 肝,腎上清の蛋白結合Cuは,対照群,Cd投与群に共に大部分のCuがMTより高分子量蛋白に結合して存在しているため,MT合成抑制による著変は認められなかった。7) Cd暴露に対するMT合成抑制による血清酵素活性(GOT,GPT,Al-P,LAP)および血清Cu濃度への影響は明らかでなかった。以上より,Cd暴露時にMT合成が抑制された場合,肝中CdはMT以外の蛋白に結合する割合が多くなると共に,腎へのCd移行が促進され腎中Cd濃度が高くなることが示唆された。

Effects of low protein diet and sex difference on the amounts of metallothionein in liver and kidney of cadmium-administered rats

Abstract Cadmium (Cd) was orally administered in a dose of 100 μg daily for a total of 100 times to investigate the effects of the intake of low (5%) protein diet and sex difference on the amounts of metallothionein (MT) in the liver and kidney. The amount of MT in the liver was significantly increased by the intake of low protein diet. In females, the increase in the amount of MT was proportional to the amount of Cd accumulated. The concentration of copper-thionein in the liver was higher in females than in males and further increased after intake of low protein diet. The levels of MT, cadmium-thionein, zinc-thionein and copper-thionein in the kidney were not influenced by the intake of low protein diet nor did show a sex difference.

Implantation disturbance studies with linear alkylbenzene sulphonate in mice

Problems were evaluated in ICR mice concerning the implantation disturbance of linear alkylbenzene sulphonate (LAS). An experiment was made to determine the incidence of implantation disturbance, distribution in the body organs, and mutagenicity of LAS administered in early pregnancy. Approximately 14, 70, or 350 mg/kg of LAS was administered orally once on day 3 of gestation or once daily from day 1 to day 3 of gestation, for 3 consecutive days. There was no significant difference in the incidence of implantation disturbance between any treated group and the control group. A single dose of 350 mg/kg of LAS was administered orally to investigate the distribution of LAS in the liver, kidney, reproductive organs (uterus and ovaries), and gastrointestinal tract 4 and 8 hr after administration on day 3 of gestation. In the liver, C10–11 components were more rapidly metabolized and C12–13 components remained unchanged. The LAS was not detected in the reproductive organs. On day 3 of gestation, LAS was administered in a single oral dose of 2 mg/mouse and on day 18 of gestation, each animal was sacrificed. On day 17 of gestation, each animal received a subcutaneous dose of 1, 2 or 10 mg/mouse and was sacrificed 24 hr later to test the mutagenicity of LAS using the micronucleusin vivo test. There was no difference among treated groups in the incidence of polychromatic erythrocytes with micronuclei in the maternal bone marrow and the fetal liver and blood. No mutagenicity was found in any of the groups.