大豆异黄酮对去卵巢大鼠体重及食物利用率的影响

目的研究植物雌激素大豆异黄酮对模拟妇女绝经的去卵巢大鼠体重增加的抑制作用及其降低体内食物利用率的作用。方法4月龄雌性Wistar大鼠腹腔假手术或切除双侧卵巢,分为假手术对照组(Sham)、去卵巢对照组(Ovx)、雌激素对照组(EC)和3个大豆异黄酮剂量组,另设正常对照组。用自行配制的含有己烯雌酚和不同剂量大豆异黄酮的饲料喂养16周,实验期间记录各组大鼠的体重和摄食情况,并计算食物利用率。结果高剂量大豆异黄酮(187.4mgkgbw·d)和己烯雌酚可显著抑制大鼠去卵巢后的体重增加;剂量降低,抑制作用减弱。与Sham组和Ovx组相比,大豆异黄酮组大鼠摄食量显著降低,但3个剂量组间没有差异且高于EC组。与OVX组相比,高剂量大豆异黄酮组大鼠食物利用率显著降低,但高于EC组。大豆异黄酮对大鼠的生长状态及脏体比值没有影响。结论高剂量大豆异黄酮可通过降低体内食物利用率而显著抑制大鼠去卵巢后体重的增加。     

Effects of taurine supplementation on bone mineral density in ovariectomized rats fed calcium deficient diet

Taurine supplementation has been shown to have a beneficial effect on femur bone mineral content in ovariectomized rats. It therefore seemed desirable to find out whether the beneficial effect of taurine on ovariectomized rats fed calcium deficient diet could also be reproduced. Forty female Sprague-Dawley rats were divided into two groups. One group was OVX and the other group received sham operation (SHAM), and received either control diet or a taurine supplemented diet for 6 weeks. All rats were fed on calcium deficient diet (AIN-93: 50% level of calcium) and deionized water. Bone mineral density (BMD) and bone mineral content (BMC) were measured in spine and femur. The serum and urine concentrations of calcium and phosphorus were determined. Bone formation was measured by serum osteocalcin and alkaline phosphatase (ALP) concentrations. Bone resorption rate was measured by deoxypyridinoline (DPD) crosslinks immunoassay and corrected for creatinine. Urinary calcium and phosphorus excretion, osteocalcin in blood and cross link value were not significantly different among the groups. Within the OVX group, the taurine supplemented group had not higher femur bone mineral content than the control group. This study established the need for a study on the taurine effect on bone with different calcium levels.     

Retrograded tapioca starch prevents ovarian hormone deficiency-induced hypercholesterolemia

The purpose of this study was to examine whether retrograded tapioca starch (RS3-tapioca) prevents ovarian hormone deficiency-induced hypercholesterolemia. Six-month-old Wistar female rats were subjected to sham-operation or ovariectomy, and fed a cholesterol-free purified diet with or without RS3-tapioca (150 g/kg diet) instead of digestible cornstarch for 28 d. Body weight gain and food intake increased in ovariectomized rats (OVX-rats). Plasma total cholesterol concentration was lowered by RS3-tapioca in OVX rats, but not in sham-operated rats. Liver lipids increased in OVX-rats, but liver cholesterol concentration was not affected by ovariectomy and RS3-tapioca. CYP7A1 activity, small intestinal and cecal bile acid content, and fecal bile acid excretion were increased by RS3-tapioca. The ratio of cholic acid groups to chenodeoxycholic acid groups in the bile acid of the small intestine was increased by RS3-tapioca. Thus, the preventive effect of RS3-tapioca on the ovarian hormone deficiency-associated increase in plasma cholesterol concentration appears to be mediated by accelerated fecal excretion of bile acid and an increase in the intestinal pool of bile acid.     

L-carnitine supplementation does not promote weight loss in ovariectomized rats despite endurance exercise

In this five-week study, we tested the hypotheses that free access to a maintenance diet supplemented with L-carnitine (L-C) would reduce body fat in adult, sedentary, ovariectomized (OVX) rats, and that there would be an additive effect of L-C on weight reduction in swim-trained animals. As expected, serum carnitine was higher in rats fed the L-C diet, and the OVX-induced weight gain and abdominal fat were counteracted by swimming. L-C supplementation did not reduce the weight gain or abdominal fat in these adult female rats, Moreover, though not reaching statistical significance, rats that were fed L-C demonstrated a tendency for greater weight gain than their basal-fed counterparts despite no difference in energy intake. If the results of this study on ovariectomized rats can be translated to postmenopausal women, moderate intensity exercise may be recommended, but L-C supplementation, with no energy restriction, may be contraindicated as a weight loss method in this cohort.     

Ovariectomy-induced hyperphagia does not modulate bone mineral density or bone strength in rats

The ovariectomized (OVX) rat is a widely used animal model for the development of prevention and treatment strategies for postmenopausal osteoporosis. However, ovariectomy-induced hyperphagia results in weight gain and adiposity. To prevent potential protective effects of increased body weight on bone from confounding outcomes of preclinical studies, pair-feeding is used in some but not all studies to control food intake, but its importance is not well elucidated. We investigated if the type of feeding, pair-feeding vs. consumption of diet ad libitum, modulates bone mineral and bone strength in OVX rats. Three-month-old female Sprague-Dawley rats (n = 12/group) were randomized to 1) sham-operated control (SHAM); 2) OVX pair-fed (OVX-PF); and 3) OVX ad libitum (OVX-AL). For 14 wk, OVX-PF rats were pair-fed with the SHAM group and daily food intakes and weekly body weights were obtained. At necropsy, regional body composition was measured by dual energy X-ray absorptiometry. Bone mineral density (BMD) and biomechanical bone strength of femurs and lumbar vertebrae (LV) were also measured. OVX-AL rats had higher overall food intake (P < 0.01), final body weight (P < 0.01), weight gain (P < 0.01), and fat mass (P < 0.05) than either SHAM and OVX-PF rats. Conversely, SHAM rats had higher femur (P < 0.001) and LV1-3 BMD (P < 0.001) as well as LV4 peak load (P < 0.01) than both the OVX groups, whereas bone outcomes did not differ between the OVX-PF and OVX-AL groups. In summary, ovariectomy-induced hyperphagia and weight gain do not modulate BMD or biomechanical strength at 14 wk postovariectomy, suggesting that pair-feeding is not essential.     

Effect of dietary legumes on bone-specific gene expression in ovariectomized rats

In previous studies, we found that the consumption of legumes decreased bone turnover in ovariectomized rats. The purpose of the present study is to determine whether the protective effects on bone mineral density (BMD) and the microarchitecture of a diet containing legumes are comparable. In addition, we aim to determine their protective actions in bones by studying bone specific gene expression. Forty-two Sprague-Dawley rats are being divided into six groups during the 12 week study: 1) rats that underwent sham operations (Sham), 2) ovariectomized rats fed an AIN-93M diet (OVX), 3) ovariectomized rats fed an AIN-93M diet with soybeans (OVX-S), 4) ovariectomized rats fed an AIN-93M diet with mung beans (OVX-M), 5) ovariectomized rats fed an AIN-93M diet with cowpeas (OVX-C), and 6) ovariectomized rats fed an AIN-93M diet with azuki beans (OVX-A). Consumption of legumes significantly increased BMD of the spine and femur and bone volume of the femur compared to the OVX. Serum calcium and phosphate ratio, osteocalcin, expression of osteoprotegerin (OPG), and the receptor activator of nuclear factor κB ligand (RANKL) ratio increased significantly, while urinary excretion of calcium and deoxypyridinoline and expression of TNF-α and IL-6 were significantly reduced in OVX rats fed legumes, compared to OVX rats that were not fed legumes. This study demonstrates that consumption of legumes has a beneficial effect on bone through modulation of OPG and RANKL expression in ovariectomized rats and that legume consumption can help compensate for an estrogen-deficiency by preventing bone loss induced by ovarian hormone deficiency.     

The effect of seamustard on blood lipid profiles and glucose level of rats fed diet with different energy composition

Recently, Korean people are consuming seaweeds almost 3.5 times more now than three decades ago. It is well known that seaweeds contain lots of soluble dietary fiber in addition to micronutrients such as β-carotene, iodine and some bioactive components. Seaweeds are considered to be effective for preventing chronic diseases including obesity, diabetes mellitus, atherosclerosis, cancer or constipation. This study was conducted to investigate the effect of seamustard intake on body weight gain, blood glucose level and lipid profiles in rats fed diets with different energy nutrient composition. Male Sprague-Dawley rats (average initial weight 103.7 g) were divided into groups for two experiments as follows; Control, M2.5 & M5 groups (Exp. I) and M5, M10, HCM5, HCM10, HFM5 & HFM10 groups (Exp. II). The rats were fed diet and water ad libitum for 4 weeks. In general, there was no significant difference in blood glucose and triglyceride concentration among groups. In Exp. I, serum LDL-cholesterol level of rats fed diet with 5% seamustard powder (M5) was significantly lower than that of control group, while HDL-cholesterol level, TC/LDL ratio and weight of adrenal gland were higher. In Exp. II, food intake, body weight gain and EER of high fat diet with 10% seamustard group (HFM10) were the lowest among groups. Except gastrocnemius muscle, all organ weights of HFM10 group were the lowest. Fecal cholesterol excretion and serum LDL-cholesterol concentration of HFM10 group were the highest, while serum HDL-cholesterol level was the lowest among groups. Interestingly, HDL-cholesterol concentration was the highest in HCM5 group among groups. From these results, it was suggested that seamustard intake might be more effective for body weight control, but not for improving blood lipid profiles in high fat diet than in high carbohydrate diet.     

Consumption of legumes improves certain bone markers in ovariectomized rats

Soybeans are known to protect against osteoporosis, but other legumes frequently consumed in Asia have not been studied to learn if they have a similar protective effect. This study investigated the hypothesis that consumption of soybean, mung bean, cowpea, and adzuki bean has beneficial effects on bone biomarkers in ovariectomized rats. Female Sprague-Dawley rats were either sham operated (sham; n = 7) or surgically ovariectomized and then fed a regular AIN-93M diet (OVX; n = 7) or AIN-93M containing soybean (n = 7), mung bean (n = 7), cowpea (n = 7), or adzuki beans (n = 7) for 10 weeks. No bean consumption significantly altered the body, subcutaneous fat, or uterus weight; however, consumption significantly increased the serum calcium/phosphorous ratio and decreased urinary calcium excretion compared with those of the OVX group. Serum concentration of 17β-estradiol was significantly lower in the OVX group compared with that of the sham group and was lowest in the group fed OVX diet containing soybean. Serum osteocalcin concentration was significantly higher in all OVX rats given a diet with beans compared with the same diet without, but urinary deoxypyridinoline excretion was lowest in the group fed OVX diet containing cowpea. There were no significant differences in bone mineral density or bone mineral content of the right femur, tibia, or lumbar spine or in the trabecular bone volume of the tibia among the diet groups. In conclusion, the consumption of soybean, mung bean, cowpea, and adzuki bean in OVX rats improved osteocalcin, but only those fed cowpea showed decreased bone resorption biomarker, suggesting that cowpea may have the most protective effect on bone in OVX rats.     

The selective estrogen receptor modulator acolbifene reduces cholesterolemia independently of its anorectic action in control and cholesterol-fed rats

The cancer-preventing selective estrogen receptor modulator (SERM) acolbifene (ACOL) exerts a potent and pure antiestrogenic action in the mammary gland and uterus, yet it displays beneficial, estrogen-like actions on energy and lipid metabolism in rodents. The compound reduces food intake and strongly decreases cholesterolemia in rats fed a cholesterol-free diet. This study was designed to establish whether the anorectic effect of ACOL is involved in its cholesterol-lowering action, and whether the compound retains its ability to lower cholesterol concentrations in rats with diet-induced hypercholesterolemia. Female rats were fed a purified diet devoid of cholesterol (reference diet) or containing 2% cholesterol (C-diet); they were either not treated or treated daily with ACOL or not treated and pair-fed to the ACOL-treated rats. The C-diet did not affect food intake or weight and fat gains. ACOL reduced food intake (16%) and weight gain (45%, mainly fat) similarly in both dietary cohorts. ACOL, but not pair feeding, reduced cholesterolemia by 33% in rats fed the reference diet. As expected, the C-diet raised serum total cholesterol almost 3-fold and this increase was largely prevented by ACOL but not by pair feeding. Cholesterol was reduced by ACOL, mainly in the HDL fraction, in rats fed the reference diet, but only in the non-HDL fraction in those fed the C-diet. In livers of rats fed the reference diet, ACOL, but not pair feeding, increased protein abundance of the scavenger receptor, class B, type 1, and the LDL receptor, thought to be involved in ACOL-mediated cholesterol lowering. These findings demonstrate that the potent hypocholesterolemic action of ACOL is independent of the concomitant reduction in food intake and fat accretion, and that such action occurs in rats with overt diet-induced hypercholesterolemia.     

Conjugated linoleic acid reduces body weight gain in ovariectomized female C57BL/6J mice

Estrogen is an important protective factor against obesity in females. Therefore, postmenopausal women have a higher rate of obesity than premenopausal women, which is associated with age-related loss of ovary function. It has been reported that a diet containing conjugated linoleic acid (CLA) reduced body weight and body fat mass in the animal model as well as in human trials. We hypothesized that ingestion of CLA would reduce body weight gain in ovariectomized (OVX) female C57BL/6J mice that is a model for postmenopaual women. We further hypothesized that body weight reduction may improve obesity-related complication. To test this hypothesis, the OVX mice were fed with a high-fat diet containing CLA for 3 months. Mice had significantly reduced body weight gain compared with OVX mice fed with a high-fat diet without CLA. Although CLA was effective in slowing down body weight gain of both sham and OVX mice, analysis of adipocyte size and number suggested different mechanisms for loss of fat tissue in these 2 groups of mice. Treatment with CLA did not increase liver weight and accumulation of fat in the livers of OVX mice. Furthermore, CLA intake did not change insulin resistance. Our results indicate that CLA is functional as an antiobesity supplement in the mouse model for postmenopausal women and that the antiobesity effect of CLA is not estrogen related.     

Blackcurrant (Ribes nigrum L.) Extract Exerts Potential Vasculoprotective Effects in Ovariectomized Rats,Including Prevention of Elastin Degradation and Pathological Vascular Remodeling

Estrogen exerts cardioprotective effects in menopausal women. Phytoestrogens are plant-derived substances exhibiting estrogenic activity that could beneficially affect vascular health. We previously demonstrated that blackcurrant (Ribes nigrum L.) extract (BCE) treatment exerted beneficial effects on vascular health via phytoestrogenic activity in ovariectomized (OVX) rats, which are widely used as menopausal animal models. Here, we examined whether BCE treatment reduced elastin degradation and prevented pathological vascular remodeling in OVX rats fed a regular diet (OVX Control) or a 3% BCE-supplemented diet (OVX BCE), compared with sham surgery rats fed a regular diet (Sham) for 3 months. The results indicated a lower staining intensity of elastic fibers, greater elastin fragmentation, and higher α-smooth muscle actin protein expression in OVX Control rats than in OVX BCE and Sham rats. Pathological vascular remodeling was only observed in OVX Control rats. Additionally, we investigated matrix metalloproteinase (MMP)-12 mRNA expression levels to elucidate the mechanism underlying elastin degradation, revealing significantly upregulated MMP-12 mRNA expression in OVX Control rats compared with that in Sham and OVX BCE rats. Together, we identify BCE as exerting a vascular protective effect through reduced MMP-12 expression and vascular smooth muscle cell proliferation. To our knowledge, this is the first report indicating that BCE might protect against elastin degradation and pathological vascular remodeling during menopause.     

Sugar beet fiber suppresses ovarian hormone deficiency-induced hypercholesterolemia in rats

The effect of sugar beet fiber (SBF) in reducing the ovariectomy-induced elevation in plasma cholesterol concentration was studied in 6-week-old, female ovariectomized (ovx) rats. Rats were subject to ovariectomy or sham operation, and fed a fiber-free diet (FF diet) or FF diet containing SBF (100 g/kg diet, SBF diet) for 42 days. The food intake, intake of nutrient fraction, body weight gain and liver weight were significantly higher in the ovx-rats than in the sham-operated rats. Among the ovx-rats, the plasma total and non-HDL cholesterol concentrations were significantly lower (by 29% and 47%, respectively) in those fed the SBF diet than in those fed the FF diet. The following parameters among the ovx-rats were significantly higher in those fed the SBF diet than in those fed the FF diet: cholesterol 7-hydroxylase activity, fecal excretion of bile acids, and cecal pool of propionic acid.     

Effects of soybean isoflavone dosage and exercise on the serum markers of bone metabolism in ovariectomized rats

This study was designed to determine whether combined treatments with soybean isoflavone dosage and moderate exercise would exhibit synergistically effects on bone metabolism following the onset of menopause. Fifty 12 wk-old female Wistar rats were assigned to five groups: 1) Sham operated (Sham), 2) ovariectomized (OVX), 3) OVX received soybean isoflavone (OVX-IF), 4) OVX exercised (OVX-EXE) and 5) OVX treated with both soybean isoflavone and exercise (OVX-IF-EXE). All rats were fed a normal diet ad libitum. Daily soybean isoflavone dosage was 50 mg/kg body weight. The vehicle was given in Sham, OVX and OVX-EXE groups. The drugs were all oral administered using a stomach tube. Exercising rats were trained on an uphill treadmill at 20 m/min for 1h/day, 5 days/week. The experimental duration consisted of the adaptation periods of 2 weeks and treatment periods of 8 weeks. The results showed that the uterus relative weights in OVX-EXE, OVX-IF and OVX-IF-EXE groups were all lower than those in Sham, they were higher than those in the OVX group. Serum alkaline phosphates (AKP) activities of OVX was significantly increased as compared to that of Sham (p<0.01). OVX-IF and OVX-IF-EXE respectively decreased the Serum alkaline phosphates activities, as compared to that of OVX (p<0.01). The tartrate-resistant acid phosphatase (TRAP) value of OVX was significantly increased as compared to that of Sham (p<0.05). OVX-IF decreased the TRAP as compared to that of OVX (p<0.05). These results suggest soybean isoflavone and resistance exercise both can restrain ovx-induced bone loss. But their mechanisms may be different.     

Hypocholesterolaemic effect of water-insoluble fish protein from Alaska pollock in ovariectomised rats is not abolished by methionine addition

The present study investigated whether the hypocholesterolaemic effect of water-insoluble fish protein (IFP) from Alaska pollock in ovariectomised (OVX) rats was affected by methionine (Met) addition. OVX rats (6 months old) were fed a cholesterol-free diet containing casein, IFP or IFP+Met as a protein source for 28?d. The ratio of Met:glycine was lower in the IFP and IFP+Met diets compared with the casein diet. Body-weight gain, food intake and liver lipids were not affected by the diet. Plasma total cholesterol concentration was lower in OVX rats fed the IFP diet compared with those fed the casein diet. The hypocholesterolaemic effect of the IFP diet was not abolished by Met addition. Amount of bile acids in the small-intestinal content and faecal excretion of bile acids were higher in OVX rats fed the IFP and IFP+Met diets compared with those fed the casein diet. Ileal bile acid transporter (IBAT) mRNA level and faecal excretion of bile acids were significantly lower and higher, respectively, in OVX rats fed the IFP diet compared with those fed the casein diet, but not in those fed the IFP+Met diet. Thus, the hypocholesterolaemic effect of the IFP diet seems to be mediated by increased faecal excretion of bile acids coupled with decreased reabsorption of bile acids from the ileum through a decrease in IBAT and the change in cholesterol metabolism linked to the amino acid profile.     

Hesperidin,a citrus flavonoid,inhibits bone loss and decreases serum and hepatic lipids in ovariectomized mice

The purpose of this study was to examine whether hesperidin inhibits bone loss in ovariectomized mice (OVX), an animal model of postmenopausal osteoporosis. Forty 8-wk-old female ddY mice were assigned to five groups: a sham-operated group fed the control diet (AIN-93G), an OVX group fed the control diet, an OVX+HesA group fed the control diet containing 0.5 g/100 g hesperidin, and an OVX+HesB group fed the control diet containing 0.7 g/100 g alpha-glucosylhesperidin and an OVX+17beta-estradiol (E(2)) group fed the control diet and administered 0.03 micro g E(2)/d with a mini-osmotic pump. After 4 wk, the mice were killed and blood, femoral, uterine and liver were sampled immediately. Hesperidin administration did not affect the uterine weight. In OVX mice, the bone mineral density of the femur was lower than in the sham group (P < 0.05) and this bone loss was significantly prevented by dietary hesperidin or alpha-glucosylhesperidin. The Ca, P and Zn concentrations in the femur were significantly higher in the hesperidin-fed and E(2) groups than in the OVX group. Histomorphometric analyses showed that the trabecular bone volume and trabecular thickness in the femoral distal metaphysis were markedly decreased (P < 0.05) by OVX, and alpha-glucosylhesperidin significantly prevented this bone loss. Furthermore, hesperidin decreased the osteoclast number of the femoral metaphysis in OVX mice, as did E(2). Serum and hepatic lipids were lower in mice that consumed the hesperidin-containing diets (P < 0.05) than in the OVX group fed the control diet. These results suggest a possible role for citrus flavonoids in the prevention of lifestyle-related diseases because of their beneficial effects on bone and lipids.     

Effect of palatable hyperlipidic diet on lipid metabolism of sedentary and exercised rats

OBJECTIVE: The present study was designed to examine 1) whether continuous feeding with a palatable hyperlipidic diet and cycling this diet with chow diet would affect lipid and carbohydrate metabolism in a similar way; and 2) whether the effect of chronic exercise on lipid and carbohydrate metabolism would be modified by these diet regimens. METHODS: Male 25-d-old Wistar rats were assigned to one of six groups: sedentary rats fed with chow diet; exercised (swimming 90 min/d, 5 d/wk) rats fed with chow diet; sedentary rats fed with a palatable hyperlipidic diet; exercised rats fed with the palatable hyperlipidic diet; sedentary rats fed with food cycles (four cycles alternating the chow and hyperlipidic diets weekly); and exercised rats fed with food cycles. After 8 wk of treatment, the animals were killed 24 h after the last exercise session. RESULTS: The hyperlipidic diet and food cycles schedules caused similar increases in body weight gain, carcass lipogenesis rate and adiposity, lipid content of the liver and gastrocnemius muscle, and serum total lipid, triacylglycerol, insulin, and leptin levels. The exercise attenuated body weight gain, adipose tissue mass, and serum triacylglycerol, insulin, and leptin levels similarly in the hyperlipidic and food cycles groups. Carcass lipogenesis rate was not affected by exercise in any of the three groups. CONCLUSIONS: The data showed that the continuous intake of a hyperlipidic palatable diet for 8 wk and the alternation of the high-fat intake with periods of chow intake cause obesity and affected lipid metabolism in a similar way. Chronic exercise attenuated body weight gain and adiposity and improved serum lipid concentrations in both high-fat feeding regimens.     

Behavioral and Metabolic Effects of a Calorie-Restricted Cafeteria Diet and Oleuropein Supplementation in Obese Male Rats

Diet-induced obesity models are widely used to investigate dietary interventions for treating obesity. This study was aimed to test whether a dietary intervention based on a calorie-restricted cafeteria diet (CAF-R) and a polyphenolic compound (Oleuropein, OLE) supplementation modified sucrose intake, preference, and taste reactivity in cafeteria diet (CAF)-induced obese rats. CAF diet consists of high-energy, highly palatable human foods. Male rats fed standard chow (STD) or CAF diet were compared with obese rats fed CAF-R diet, alone or supplemented with an olive tree leaves extract (25 mg/kg*day) containing a 20.1% of OLE (CAF-RO). Biometric, food consumption, and serum parameters were measured. CAF diet increased body weight, food and energy consumption and obesity-associated metabolic parameters. CAF-R and CAF-RO diets significantly attenuated body weight gain and BMI, diminished food and energy intake and improved biochemical parameters such as triacylglycerides and insulin resistance which did not differ between CAF-RO and STD groups. The three cafeteria groups diminished sucrose intake and preference compared to STD group. CAF-RO also diminished the hedonic responses for the high sucrose concentrations compared with the other groups. These results indicate that CAF-R diet may be an efficient strategy to restore obesity-associated alterations, whilst OLE supplementation seems to have an additional beneficial effect on sweet taste function.     

食物不同营养素配比与限食对大鼠营养状况的影响

目的 了解饲料营养素配比与限食对大鼠营养状况的影响。方法 用低脂低蛋白（A组），正常（B组），高脂高蛋白（C组）限食喂养3组幼鼠各4周，观察幼鼠体重增重，食物功效比（FER）及血红蛋白的变化。结果 在不同营养素配比饲料喂养下，雄性幼鼠A组前2周中体重与B、C组的差异有显意义，后2周则赶上B、C组；在A、C组限食喂养量后，雄鼠反应强烈，雌鼠体重增重量逐渐下降，直至出现负增长。不同营养素配比的饲料无论足量或限量喂养，A、C组的FER均低于B组。雌、雄大鼠A组的血红蛋白值始终低于B、C组，差异有显意义。结论 体重增长与总热能摄入量有关；营养素的合理配比可提高食物的利用率；蛋白质与脂类的含量在血红蛋白合成中具有重要意义。     

Genistein reduced insulin resistance index through modulating lipid metabolism in ovariectomized rats

Postmenopausal women are at higher risk for obesity and insulin resistance due to the decline of estrogen, but genistein, a phytoestrogen, may reduce the risks of these diet-related diseases. In this study, we hypothesized that supplemental genistein has beneficial effects on insulin resistance in an ovariectomized rat model by modulating lipid metabolism. Three weeks after a sham surgery (sham) or an ovariectomy (OVX), ovariectomized Sprague-Dawley rats were placed on a diet containing 0 (OVX group) or 0.1% genistein for 4 weeks. The sham rats were fed a high-fat diet containing 0% genistein and served as the control group (sham group). The ovariectomized rats showed increases in body weight and insulin resistance index, but genistein reduced insulin resistance index and the activity of hepatic fatty acid synthetase. Genistein was also associated with increased activity of succinate dehydrogenase and carnitine palmitoyltransferase and the rate of β-oxidation in the fat tissue of rats. The ovariectomized rats given genistein had smaller-sized adipocytes. Using gene-set enrichment analysis (GSEA) of microarray data, we found that a number of gene sets of fatty acid metabolism, insulin resistance, and oxidative stress were differentially expressed by OVX and reversed by genistein. This systemic approach of GSEA enables the identification of such consensus between the gene expression changes and phenotypic changes caused by OVX and genistein supplementation. Genistein treatment could help reduce insulin resistance through the amelioration of OVX-induced metabolic dysfunction, and the GSEA approach may be useful in proposing putative targets related to insulin resistance.