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Nutrition and light-dark cycle influence rat testicular development. With 9% casein diet (low protein diet) under normal 12 h-12 h lighting cycles (9P), juvenile rat testes undergo normal growth. On the other hand, a low protein diet with constant darkness (D9P) results in a growth arrest of rat testes. Supplementation of cystine to the low protein diet under constant darkness (D9PC) had a tendency to increase testes weight, suggesting an improvement in growth suppression. Whether the growth suppression of testes in D9P is associated with suppression of spermatogenesis has not yet been shown. We aimed to determine the effect of a low protein diet and constant darkness with or without dietary cystine in testes using a histological technique. In the histological assessment, D9P testes showed a decreased number of seminiferous tubules with elongated spermatids, indicating a functional testicular defect in this group. However, cystine supplementation resulted in enhanced spermatogenesis versus control animals (D9PC vs. D9P) implying the importance of cystine to testicular development in this condition. Furthermore, serum testosterone concentration was increased in D9PC suggesting contribution of testosterone to ameliorate spermatogenesis. From these results, we conclude that cystine supplementation to a low protein diet under constant darkness promoted an increase in testosterone which in turn benefitted spermatogenesis.

The purpose of this study is to further the search for the optimal conditions for the recovery of recycled carbon fiber (rCF) from epoxy matrix CFRP by thermal decomposition. We revealed that an oxidizing atmosphere was required to recover rCF. By investigating the strength reduction of CF after the heat treatment (hCF), it was demonstrated that significant strength reduction occurred at 600 °C. The damage also depended on the treatment temperature and time because of the oxidative decomposition of the fiber surface. By comparing the virgin CF, hCF and rCF, it was demonstrated that the strength reduction of the rCF was caused not only by the thermal oxidative decomposition but also by its interaction with the resin. Additionally, the time required to recover rCF differs depending on the treatment temperature and the degree to which each effect on the CF in CFRP depended on the location of the CF. At low temperatures, recovery time was longer, and the differences in strength between rCF recovered from the inner and outer layers were large. although CF recovery was quick at high temperatures, but the strength was significantly lower because of the effect of the interaction with the resin.

The purpose of this study was to clarify the effects of dietary protein levels on protein nutritional status in rats kept under constant darkness. Thirty-six 4-wk-old female rats (F344 strain) were divided into six groups. Each group was given a diet with one of three different protein levels and kept under normal light and dark cycles (7:00-19:00 light period/19:00-7:00 dark period, N group) or under constant darkness (D group) for 4 wk. The protein levels of the diets were 10%, 20%, and 30% casein. The six groups are referred to as the N10%, N20%, N30%, D10%, D20%, and D30% groups. Body weight gain was low in the D groups, and that in the D30% group was much lower than that in the N30% group. The D30% group retained less nitrogen than the N30% group. As for the amount of urinary nitrogen excreted every 4 h, the values for the D-groups were higher than those for the N-groups in the 11:00-15:00 periods, and that for the D30% group was higher than that for the N30% group in the 15:00-19:00 periods, which means that protein catabolism was higher in the D30% group. It was shown that when rats kept under constant darkness were fed a high-protein diet for 4 wk, their nitrogen retention decreased and their protein nutritional state dropped.

The purpose of this study was to determine whether the effects of dietary protein on sexual organ development were different in mice and rats kept under constant darkness. Four-week-old mice (ICR strain) and rats (F344 strain) were kept under constant darkness (D) or normal lighting (N; 12-h light/dark cycle) for 4 wk. The dietary protein level was 9% casein with the addition of 0.135% cystine (9PC) or without it (9P); other components of the diet were based on the AIN-93G diet. The testes and epididymides weights (g/100 g BW) of the rats given the 9P diet in the D-group were lower than those of the rats given the 9P diet in the N-group. In the mice, lighting conditions and diet did not affect testes or epididymides weights. Body weight and food intake in the rats were affected by diet, and these values were lower in the 9P diet group; however, body weight and food intake in the mice was not affected by diet. The serum albumin concentration in the rats was lower in the 9P diet group, while that of the mice was lower in the 9PC diet group. In the rats kept under constant darkness, a diet lacking in cystine accelerated the suppression of sexual organ development and decreased serum albumin concentration, but this diet had no such effects on the mice. The finding that the effects of dietary protein were different in mice and rats suggests that protein requirements of mice are different from those of rats.

The purpose of this study was to clarify the effects of nutrients on the gonadal development of male rats kept under constant darkness as a model of disturbed daily rhythm. In the present study we examined fat-soluble vitamins and their interactions in this test population. Four fat-soluble vitamins (vitamin A (V.A), vitamin D (V.D), vitamin E (V.E) and vitamin K (V.K)) were selected as experimental factors, and the dietary content of these vitamins was normal (AIN-93G) or three times the normal content. Lighting conditions (constant darkness or normal lighting) were also added as a factor. Four-week-old rats (Fischer 344 strain) were kept under constant darkness or normal lighting (12-h light/dark cycle) for 4 wk. The lighting condition and V.E, and the interactions between the lighting condition and V.E and between V.A and V.D were observed to affect the testes and epididymides weights. There was an influence of the lighting condition only on the seminal vesicles and prostate weights and the serum testosterone concentration. Among the constant darkness groups (D-groups), the highest value for testes weight was observed under the normal-V.A, normal-V.D and high-V.E diet. The interaction between lighting condition and V.E showed the testes weight increased slightly in response to changing to a high-V.E diet from a normal-V.E diet under normal lighting (N-group) but was greatly increased in response to this change in the D-group. It became clear that the amount of dietary V.E necessary for the gonadal development of rats increases when rats are kept under constant darkness.

The purpose of this experiment was to clarify the effects of dietary protein levels on the gonadal development and sex hormones in male rats kept under constant darkness as a model of disturbed daily rhythm. Four-week-old male rats (Fischer 344 strain) were kept under constant darkness or normal lighting (12-h light/dark cycle). Two kinds of experimental diet were prepared, one with low dietary protein levels (9% casein) and one with normal levels (18% casein). Harper mineral mixture and Panvitan were used as mineral and vitamin sources, respectively. After 4 weeks, gonadal weight, serum testosterone, and other hormone contents were evaluated. The gonadal weight in the constant darkness groups (D-groups) was lower than that in the normal lighting groups (N-groups). Although the low-protein diet in the D-groups significantly reduced gonadal weight, the normal-protein diet mitigated the reduction of gonadal weight in rats kept under constant darkness. Serum testosterone and androstenedione concentrations were lower in D-group rats fed the low-protein diet. There were no effects of lighting condition or protein levels on serum luteinizing hormone (LH), follicle- stimulating hormone (FSH), or progesterone concentrations. These results indicate that the suppression of gonadal development in D-group rats fed the low-protein diet was caused by low testosterone, which we attribute to the inhibition of synthesized androstenedione, a precursor of testosterone. The present study showed that constant darkness and the low- protein diet inhibited the synthetic pathway from progesterone to androstenedione.

The purpose of this study was to clarify the effects of nutrients on the gonadal development of male rats kept under constant darkness as a model of disturbed daily rhythm. In the present study we examined fat-soluble vitamins and their interactions in this test population. Four fat-soluble vitamins (vitamin A (V.A), vitamin D (V.D), vitamin E (V.E) and vitamin K (V.K)) were selected as experimental factors, and the dietary content of these vitamins was normal (AIN-93G) or three times the normal content. Lighting conditions (constant darkness or normal lighting) were also added as a factor. Four-week-old rats (Fischer 344 strain) were kept under constant darkness or normal lighting (12-h light/dark cycle) for 4 wk. The lighting condition and V.E, and the interactions between the lighting condition and V.E and between V.A and V.D were observed to affect the testes and epididymides weights. There was an influence of the lighting condition only on the seminal vesicles and prostate weights and the serum testosterone concentration. Among the constant darkness groups (D-groups), the highest value for testes weight was observed under the normal-V.A, normal-V.D and high-V.E diet. The interaction between lighting condition and V.E showed the testes weight increased slightly in response to changing to a high-V.E diet from a normal-V.E diet under normal lighting (N-group) but was greatly increased in response to this change in the D-group. It became clear that the amount of dietary V.E necessary for the gonadal development of rats increases when rats are kept under constant darkness.

出納実験時に糞採取マーカーとして0.1%カルミン添加食を用いる必要性について検討した。フィッシャー系3週齢の雄ラット24匹をAIN-93G飼料にて1週間予備飼育後, 4群に分けた。実験飼料は2種; AIN-93飼料G (M) (Con) または, 糖質源をすべてスクロースにした飼料 (Suc) であり, 出納実験手法は2手法; マーカー使用群 (M) またはマーカー非使用群 (NM) とした。それぞれをConM群, ConNM群, SucM群, SucNM群とした。出納実験は, 本飼育開始直後 (1週目, I期), 3週目 (II期), 5週目 (III期), 5カ月目 (IV期) および7カ月目 (V期) にそれぞれ4日間 (V期のみ3日間) 実施した。M群には出納実験開始日と終了日に0.1%カルミン添加食 (赤色に着色) を与え, 翌日の糞採取の際, 赤色糞と白色糞を分別採取した。NM群は出納実験期間の糞をすべて採取した。乾燥糞重量, カルシウム吸収率から糖質源の差, 出納実験実施の時期の違いも含め, マーカー使用有無の影響を検討した。その結果, 出納実験開始翌日の糞には, 前々日由来の糞が排泄されることが示され, その量は加齢とともに増加することが示された。また, I期のSucM群とSucNM群の乾燥糞重量, カルシウム吸収率に差が認められた。ConM群とConNM群には差は認められず, その他の出納実験期でも糞重量にマーカー使用有無の影響は認められなかった。以上の結果から, 飼料交換直後に出納実験をする際, および週齢の異なる群間を比較する際などには, マーカーを使用する必要性があることが明らかとなった。同一飼料が継続的に給与されている場合は, ラットがコンスタントに飼料を摂取しコンスタントに糞を排泄しているという前提のもと, マーカーを使用しない出納実験が可能であると考えられた。

The purpose of this study was to clarify the effects of nutrients on the gonadal development of male rats kept under constant darkness as a model of disturbed daily rhythm. The present study examined protein and vitamins, and their interactions. This study was based on three-way ANOVA; the three factors were lighting conditions, dietary protein and dietary vitamins, respectively. The levels of dietary protein were low or normal: 9% casein or 20% casein. The levels of dietary vitamins were low, normal or high: 1/3.3 of normal (AIN-93G diet) content, normal content, or three times the normal content, respectively. Other compositions were the same as those of the AIN-93G diet, and six kinds of experimental diet were prepared. Four-week-old rats (Fischer 344 strain) were kept under constant darkness or normal lighting (12-h light/dark cycle) for 4 wk. After 4 wk, the gonadal weights and serum testosterone content were evaluated. In the constant darkness groups (D-groups), the low-protein diet induced reduction of gonadal organ weights and serum testosterone concentrations. This reduction of gonadal organ weights was exacerbated by progressively higher levels of dietary vitamins. In the case of a normal-protein diet, the depression of gonadal development was not accelerated by high-vitamin intake. In the normal lighting groups (N-groups), the low-protein and high-vitamin diet slightly depressed gonadal development. These results suggest that the metabolism of protein and vitamins is different in rats being kept under constant darkness, and that excess dietary vitamins have an adverse effect on gonadal development in rats fed a low-protein diet.

There are about 40 minerals which are components of the human body. Of those, thereare 13 minerals, Ca, Fe, Mg, K, Na, P, Zn, Cu, I, Mn, Mo, Cr and Se, for which either therecommended dietary allowance (RDA) or the tolerable upper intake level (UL) wasstipulated by the Ministry of Health and Welfare (MHW) of Japan in June of 1999.Recent dietary practices have become highly dependent upon refined or purified foodingredients. Therefore, much attention has been paid to minerals which are lost or addedduring food processing. The MHW is expecting the nation to become more responsibleconcerning these foods with unbalanced mineral content and that is why the new RDAand UL have been stipulated.Adequate mineral balance may be changed by other nutrients.Therefore, determiningthe desirable ratio of minerals is not a simple matter. Viewed simply, the desirable ratiocan be calculated from the RDA values. The desirable ratio of Ca, Mg and P is 2: 1: 4.Based on the Japanese standard food composition table, foods which have a comparativelyhigh Ca content of 100mg or more per 100 g of edible material and which have adesirable Ca, Mg and P ratio were selected. There were found to be only fifteen of suchfoods among 87 food items with a comparatively high Ca content. The majority of thesefoods are basic ingredients for many Japanese dishes. There were rice-kojimiso, soybeankojimiso, okara, raw saltwort, raw okura, dried kanpyo, dried purple laver, dried arame, dried ma-konbu kelp, boiled and dried hijiki, dried wakame, finely ground green tea, currypowder, black pepper and boiled wary crab.Milk and its products were not selected as such foods because of their low Mg content. These foods should be consumed with a high-Mg food. Based on these ideas, a study onthe effects of supplementary minerals should be conducted.The health effects of dietary minerals are evident when the minerals are consumedwith appropriate nutrients simultaneously. For example, Ca is important for bone formation, but, without Mg, P, Fe, Zn, vitamin D, vitamin K, vitamin C and protein, adequatebone formation is not expected to occur.It seems possible that the unusual longevity of the Japanese may be due to the desirablemineral balance of Japanese cuisine.Also, absorption of Ca from soybeans and soybean products and other vegetableswhich are the main sources of Ca in the Japanese diet has been compared with the absorp-tion of Ca from milk and milk products which also serve as major sources of Ca in theJapanese diet.It was noticed that the absorption of Ca from soybeans, soybean productsand other vegetables was almost the same as that from milk and milk products.

We studied the extent of kidney calcification by varying dietary levels of Mg, based on pathological examinations and calcium (Ca) and magnesium (Mg) balance tests. AIN-76 diets containing varying levels of Mg--0.3 (-M), 1.3 (1/20M), 2.4 (1/10M), 9.2 (1/5M), 19 (control), 38 (2M), 102 (5M), and 187 (10M) mmol/kg diet--were fed to 3-week-old male Fischer-344 rats for 14d. Although the magnitude of abnormality was highest in kidney of rats fed the -M diet, the damage was normalized as the dietary level of Mg increased, with increasing serum Mg concentration and urinary excretion of Mg. We found almost no deposition of Ca in rats fed the 10M diet. The mechanism by which the high dietary Mg induces these effects most likely involves a competition between Mg and Ca for reabsorption in proximal and/or distal tubules, since these diets increased the urinary excretion of Ca. However, these high Mg diets decreased food intake and body weight gain compared with the control diet, although these indices were not decreased in rats fed the 2M diet. The results suggest that a dietary magnesium level approximately twice the normal level effectively reduces kidney calcification while maintaining normal growth in rats.

Mice with targeted gene disruption of one of the estrogen receptor coactivators, p300/CBP-associated factor (PCAF), and its counterpart, PCAF-B, were used to investigate the possible involvement of PCAF and PCAF-B in estrogen receptor-mediated actions in vivo. Among ovariectomized mice that were treated with estrogen, PCAF and PCAF/PCAF-B knockouts showed abnormal growth of the uterus compared with the wild type. The level of c-fos gene expression in the uterus was not induced by estrogen in the knockouts. These observations suggest that PCAF and PCAF-B are required for estrogen-dependent normal growth of the uterus via estrogen receptor-mediated transcriptional regulations.

The purpose of this study was to clarify the effects of nutrients on the gonadal development of male rats kept under constant darkness as a model of disturbed daily rhythm. In the present study we examined fat-soluble vitamins and their interactions in this test population. Four fat-soluble vitamins (vitamin A (V.A), vitamin D (V.D), vitamin E (V.E) and vitamin K (V.K)) were selected as experimental factors, and the dietary content of these vitamins was normal (AIN-93G) or three times the normal content. Lighting conditions (constant darkness or normal lighting) were also added as a factor. Four-week-old rats (Fischer 344 strain) were kept under constant darkness or normal lighting (12-h light/dark cycle) for 4 wk. The lighting condition and V.E, and the interactions between the lighting condition and V.E and between V.A and V.D were observed to affect the testes and epididymides weights. There was an influence of the lighting condition only on the seminal vesicles and prostate weights and the serum testosterone concentration. Among the constant darkness groups (D-groups), the highest value for testes weight was observed under the normal-V.A, normal-V.D and high-V.E diet. The interaction between lighting condition and V.E showed the testes weight increased slightly in response to changing to a high-V.E diet from a normal-V.E diet under normal lighting (N-group) but was greatly increased in response to this change in the D-group. It became clear that the amount of dietary V.E necessary for the gonadal development of rats increases when rats are kept under constant darkness.

An experiment was designed to evaluate the bioavailability of purple laver (Asakusa-Nori, Porphyra tenera Kjellman) magnesium (Mg) in Mg-scarcity Fischer 344 male rats from serum Mg level, kidney calcification and bone Mg contents. Male rats of 4 weeks of age were divided into four groups of six rats. The four groups were control (20SC), Mg-restricted (-Mg20SC), -Mg20SC plus purple laver (-Mg20SCP), and 20SC plus purple laver (20SCP) group respectively. To -Mg20SC, 1/10 Mg of the 20SC diet was added. -Mg20SCP diet purple laver as a Mg source. 20SCP diet was designed to contain double amount of Mg. After a 3-week experimental period, rats were decapitated. Blood serum, right kidney, and right femur were collected and Mg, calcium (Ca), phosphorus (P) were determined. Serum Mg concentration of the -Mg20SC was 1/3 of the 20SC, indicating apparent hypomagnesemia. Serum P also showed lowered concentration. On the other hand, the serum Ca indicated higher value than the other groups, indicating hypercalcemia. Addition of purple laver to -Mg20SC diet resulted in a normal serum Mg, Ca, and P level. The Mg-scarcity (-Mg20SC) rats accumulated much amount of kidney Ca. Whereas, there was no significant difference in kidney Ca between control (20SC) group and purple laver-supplemented (-Mg20SCP) rat group. The -Mg20SC rats showed lowered ash content and reduced Mg and P concentrations in the femur. Purple laver supplementation increased the ash, Mg, and P. All of the results indicated that the purple laver Mg was used as a Mg source.(ABSTRACT TRUNCATED AT 250 WORDS)

The purpose of this study was to clarify the effects of nutrients on the gonadal development of male rats kept under constant darkness as a model of disturbed daily rhythm. This experimental protocol was designed based on the L16(2(15))-type orthogonal array, which can examine six factors. Five minerals (calcium (Ca), phosphorus (P), magnesium (Mg), sodium (Na), and zinc (Zn)) were selected as experimental factors, and the dietary content of these minerals was normal (AIN-76 diet) or 1/3.5 of the normal content. Lighting conditions (constant darkness or normal lighting) were also added as a factor. Four-week-old rats (Fischer 344 strain) were kept under constant darkness or normal lighting (12-h light/dark cycle) for 4 wk. After 4 wk, the gonadal weights and serum testosterone content were evaluated. The lighting condition, Ca, Mg, and Na, and the interactions between the lighting condition and Ca, and Mg and Na were observed to affect the testes weight. Among the constant darkness groups (D-groups), the highest value for testes weight was observed under the normal-Ca, normal-Mg, and normal-Na diet, and the lowest value was observed under the low-Ca, normal-Mg, and low-Na diet. Among the normal lighting groups (N-groups), the highest value for testes weight was observed under the low-Ca, normal-Mg, and normal-Na diet, and the lowest value was observed under the normal-Ca, normal-Mg, and low-Na diet. Among the D-groups, the highest value for serum testosterone was observed under the normal-Ca, normal-Mg, and low-Na diet. Among the N-groups, the highest value was observed under the low-Ca, normal-Mg, and low-Na diet. It became clear that the amount of dietary Ca necessary for the gonadal development of rats increases when rats are kept under constant darkness as a model of disturbed daily rhythm compared with the normal lighting condition.

The purpose of this experiment was to clarify the effects of nutrients on the gonadal development of male rats kept under constant darkness as a model of disturbed daily rhythm. Protein, methionine, vitamins, minerals and fat were selected as experimental factors, and eight kinds of diets were prepared based on the L 8 (2 7 ) type orthogonal array Dietary contents of the nutrients were normal (AIN-76 diet) or 1/3 to 1/2 of the normal content. Four-week-old rats (Fischer 344 strain) were kept under constant darkness for 4 wk. Control groups were kept under 12-h light/dark cycle. After 4 wk, the gonadal weights and serum testosterone content were evaluated. The effects of nutrients on gonadal development in rats differed between constant darkness groups (D-groups) and normal lighting groups (N-groups). Among the D-groups, the highest value for testes weight was observed under the normal protein, methionine added, low vitamin, low mineral and normal fat diet. The lowest value for testes weight was observed under the low protein, methionine added, normal vitamin, normal mineral and low fat diet. Among the N-groups, the highest value for testes weight was observed under the normal protein and no methionine diet, and the lowest value was observed under the low protein and no methionine diet. Among the D-groups, the highest value for serum testosterone was observed under the normal protein and low mineral diet. In the N-groups, serum testosterone was not affected by nutritional factors. It became clear that the amounts of protein, methionine, vitamins. minerals, and oil which are necessary for the gonadal development of growing male rats change when kept in constant darkness.

The bioavailability of roasted and ground soybean (kinako) magnesium (Mg) in Fischer 344 strain male rats with respect to serum Mg level, bone Mg contents, kidney calcification, and Mg absorption was evaluated. Four-week-old male rats were divided into four groups of six rats each. The four groups were the control (20SC), Mg-deficient diet (1/3 Mg20SC), 20SCK diet, and 20SCDK diet. The 20SCK and 20SCDK diets were prepared to contain amounts of Mg equal to that in the 20SC diet with kinako or defatted kinako as the Mg source, respectively. After a 4-week experimental period, rats were decapitated and blood serum, right femur, and right kidney were collected, and Mg, calcium (Ca), and phosphorus (P) concentration in those tissues were determined. The Mg balance was also investigated. The serum Mg concentration in the 1/3 Mg20SC group was half the level in the 20SC group, and the serum Ca concentration was higher than in the 20SC group, indicating apparent hypercalcemia. Serum Mg and Ca concentrations in the 20SCK and 20SCDK groups did not significantly differ from those in the 20SC group. Femur Mg concentration in the 1/3 Mg20SC group was lower than in the 20SC group. Femur Mg concentrations in the 20SCK and 20SCDK groups were lower than in the 20SC group, but significantly higher than in the 1/3 Mg20SC group. The kidney Ca concentrations in the 20SCK and 20SCDK groups were significantly higher than those in the 20SC and 1/3 Mg20SC groups, and there was also kidney calcification. These results indicated that kinako and defatted kinako Mg were used effectively as a serum and femur Mg source, but that kinako and defatted kinako carry a risk of kidney calcification when used as the only Mg source.