Effect of a soy protein diet on serum lipids of renal transplant patients

ObjectiveThe aim of the present study was to evaluate the effect of a soy-protein diet on plasma lipid levels of renal transplant recipients with moderate hypercholesterolemia.DesignDietary intervention case-control observational study.SettingRenal transplantation outpatient clinic.PatientsFifteen stable patients who had renal transplantation (serum creatinine < 2 mg/dL) with moderate hypercholesterolemia (low-density lipoprotein [LDL] cholesterol > 140 mg/dL).InterventionAfter a baseline dietary interview, dietary counseling was given individually with the goal of substituting 25 g of animal protein with 25 g of soy protein for a 5-week period, using commercially available soy foods, according to each patient’s own preference.Main outcome measuresBefore and after the soy-diet period, plasma lipid profiles including total, LDL, and high-density lipoprotein (HDL) cholesterol, triglycerides, apolipoprotein A1 and B were determined. Protein catabolic rate was assumed as a measure of dietary protein intake.ResultsTwo patients dropped out. After the soy diet, total cholesterol (254 ± 22 to 231 ± 31 mg/dL, P < .05) and LDL cholesterol (165 ± 20 versus 143 ± 20 mg/dL, P < .01) decreased significantly. No significant changes were observed regarding HDL cholesterol and triglycerides. Dietary protein intake did not differ at baseline (73.2 ± 22.9 g/day) and during the soy diet (72.6 ± 15.6 g/day), when the reported actual soy protein intake resulted 26 ± 8 g/day.ConclusionsThis study shows that soy proteins given as part of the daily protein intake have beneficial effects on serum LDL cholesterol levels of renal transplant recipients with moderate hypercholesterolemia. Soy proteins could be of use in the nutritional management of renal transplant recipients.     

大豆蛋白对大鼠血脂调节的作用机制

目的 探讨大豆蛋白对大鼠血脂代谢的影响及其可能的作用机制.方法 SPF级雄性SD大鼠48只,进食基础饲料适应性喂养2周,随机分为4组:大豆蛋白组,酪蛋白组,大豆蛋白高脂组,酪蛋白高脂组.进食实验饲料28d.测定试验蛋白中氨基酸含量,大鼠血清中血脂、胰岛素和胰高血糖素水平.结果 与酪蛋白相比,大豆蛋白的赖/精比值小,蛋氨酸含量低,胱氨酸含量高.大豆蛋白组大鼠TC、HDL-C浓度及TC/HDL-C比值比酪蛋白组低.大豆蛋白高脂组大鼠血清TC、TG、LDL-C浓度及TC/HDL-C比值比酪蛋白高脂组低.大豆蛋白组大鼠血清胰岛素浓度比酪蛋白组低.大豆蛋白高脂组大鼠血清胰岛素浓度比酪蛋白高脂组低,胰高血糖素浓度比酪蛋白高脂组高.结论 大豆蛋白可通过影响血清中胰岛素/胰高血糖素比率及其氨基酸种类和含量来调节血脂水平,其作用机制还需进一步探讨.     

A low protein diet alters gene expression in rat pancreatic islets

Insulin secretion is regulated mainly by circulating nutrients, particularly glucose, and is also modulated by hormonal and neuronal inputs. Nutritional alterations during fetal and early postnatal periods, induced by either low protein or energy-restricted diets, produce beta-cell dysfunction. As a consequence, insulin secretion in response to different secretagogues is reduced, as is the number of beta-cells and the size and vascularization of islets. In this study, we used a cDNA macroarray technique and RT-PCR to assess the pattern of gene expression in pancreatic islets from rats fed isocaloric low (6 g/100 g, LP) and normal (17 g/100 g, NP) protein diets, after weaning. Thirty-two genes related to metabolism, neurotransmitter receptors, protein trafficking and targeting, intracellular kinase network members and hormones had altered expression (up- or down-regulated). RT-PCR confirmed the macroarray results for five selected genes, i.e., clusterin, secretogranin II precursor, eukaryotic translation initiation factor 2, phospholipase A(2) and glucose transporter. Thus, cDNA macroarray analysis revealed significant changes in the gene expression pattern in rats fed a low protein diet after weaning. The range of proteins affected indicated that numerous mechanisms are involved in the intracellular alterations in the endocrine pancreas, including impaired glucose-induced insulin secretion.     

A 4-wk high-fructose diet alters lipid metabolism without affecting insulin sensitivity or ectopic lipids in healthy humans

BACKGROUND: High fructose consumption is suspected to be causally linked to the epidemics of obesity and metabolic disorders. In rodents, fructose leads to insulin resistance and ectopic lipid deposition. In humans, the effects of fructose on insulin sensitivity remain debated, whereas its effect on ectopic lipids has never been investigated. OBJECTIVE: We assessed the effect of moderate fructose supplementation on insulin sensitivity (IS) and ectopic lipids in healthy male volunteers (n = 7). DESIGN: IS, intrahepatocellular lipids (IHCL), and intramyocellular lipids (IMCL) were measured before and after 1 and 4 wk of a high-fructose diet containing 1.5 g fructose . kg body wt(-1) . d(-1). Adipose tissue IS was evaluated from nonesterified fatty acid suppression, hepatic IS from suppression of hepatic glucose output (6,6-2H2-glucose), and muscle IS from the whole-body glucose disposal rate during a 2-step hyperinsulinemic euglycemic clamp. IHCL and IMCL were measured by 1H magnetic resonance spectroscopy. RESULTS: Fructose caused significant (P < 0.05) increases in fasting plasma concentrations of triacylglycerol (36%), VLDL-triacylglycerol (72%), lactate (49%), glucose (5.5%), and leptin (48%) without any significant changes in body weight, IHCL, IMCL, or IS. IHCL were negatively correlated with triacylglycerol after 4 wk of the high-fructose diet (r = -0.78, P < 0.05). CONCLUSION: Moderate fructose supplementation over 4 wk increases plasma triacylglycerol and glucose concentrations without causing ectopic lipid deposition or insulin resistance in healthy humans.     

A cooperative interaction between soy protein and its isoflavone-enriched fraction lowers hepatic lipids in male obese Zucker rats and reduces blood platelet sensitivity in male Sprague-Dawley rats

Soy protein diets lower plasma cholesterol in hyperlipoproteinemic human subjects, as well as in animal models. We fed 7-wk-old male obese (fa/fa) and lean Zucker rats a modified AIN-76 diet (20 g protein/kg diet) containing casein (C), low isoflavone soy protein (38 mg isoflavones/kg diet; LI), or high isoflavone soy protein (578 mg isoflavones/kg diet; HI) for 70 d. In obese rats, plasma total cholesterol was 21 and 29% lower in the LI and HI groups, respectively, than in the C group (P: 相似文献   

Polyphenol-rich strawberry pomace reduces serum and liver lipids and alters gastrointestinal metabolite formation in fructose-fed rats

This study compared the effects of supplementation with a polyphenol-rich pomace from strawberry (US) and a strawberry pomace without most of these compounds (PS) on gastrointestinal, blood, and tissue biomarkers in rats fed diets differing in carbohydrate contents for 4 wk. The diets were: corn starch (group CS), high fructose (60% by weight; group F), starch with 7.7% of either US or PS (groups CS+US and CS+PS, respectively), and high fructose with 7.7% of either US or PS (groups F+US and F+PS, respectively). An interaction (P < 0.05) was observed between diet type and strawberry preparation, showing that upon fructose feeding, US had a greater effect than PS on lowering serum insulin, liver total cholesterol, and conjugated dienes. Additionally, the F+US group had lower serum FFA than the F+PS group (P < 0.05). The extraction of polyphenols diminished the physiological effect associated with strawberry intake, suggesting that the fiber component of the pomace was also active in reducing metabolic complications following fructose feeding to rats.     

Impact of dietary protein on lipid metabolism in hamsters is source-dependent and associated with changes in hepatic gene expression

This study tested the hypothesis that protein source is a factor determining the impact of the diet on lipid metabolism in hamsters. Twenty-eight hamsters of similar body weight were assigned for a period of 8 weeks to one of the following four diets (seven per group) containing either 20 % (w/w) casein (CAS), beef protein (BF), wheat gluten (WG) or soya protein (SOY). The fat composition of the diet was the same (15.5 % w/w) in all groups and provided SFA, MUFA and PUFA representative of the average Canadian diet. After an overnight fast, blood and liver were collected for the measurement of serum lipids, fatty acid composition of liver phospholipids and mRNA levels of selected genes involved in lipid metabolism. WG resulted in lower total cholesterol, HDL-cholesterol and non-HDL-cholesterol but, along with SOY, in higher mRNA levels of cholesterol 7 alpha-hydroxylase and LDL receptor. Furthermore, both WG and SOY resulted in lower 18 : 3n-3, 20 : 4n-6, total n-6 PUFA, 18 : 1n-9 and total MUFA, but higher 22 : 6n-3, total n-3 PUFA, 22 : 6n-3/18 : 3n-3 and 22 : 5n-3/18 : 3n-3 ratios in liver phospholipids, and higher hepatic Delta6-desaturase mRNA levels. These results show that the impact of dietary protein on lipid metabolism is source-dependent and associated with changes in mRNA abundances of key hepatic enzymes and receptors.     

A short-term,high-fat diet up-regulates lipid metabolism and gene expression in human skeletal muscle

BACKGROUND: Dietary fatty acids may be important in regulating gene expression. However, little is known about the effect of changes in dietary fatty acids on gene regulation in human skeletal muscle. OBJECTIVE: The objective was to determine the effect of altered dietary fat intake on the expression of genes encoding proteins necessary for fatty acid transport and beta-oxidation in skeletal muscle. DESIGN: Fourteen well-trained male cyclists and triathletes with a mean (+/- SE) age of 26.9 +/- 1.7 y, weight of 73.7 +/- 1.7 kg, and peak oxygen uptake of 67.0 +/- 1.3 mL x kg(-1) x min(-1) consumed either a high-fat diet (HFat: > 65% of energy as lipids) or an isoenergetic high-carbohydrate diet (HCho: 70-75% of energy as carbohydrate) for 5 d in a crossover design. On day 1 (baseline) and again after 5 d of dietary intervention, resting muscle and blood samples were taken. Muscle samples were analyzed for gene expression [fatty acid translocase (FAT/CD36), plasma membrane fatty acid binding protein (FABPpm), carnitine palmitoyltransferase I (CPT I), beta-hydroxyacyl-CoA dehydrogenase (beta-HAD), and uncoupling protein 3 (UCP3)] and concentrations of the proteins FAT/CD36 and FABPpm. RESULTS: The gene expression of FAT/CD36 and beta -HAD and the gene abundance of FAT/CD36 were greater after the HFat than after the HCho diet (P < 0.05). Messenger RNA expression of FABPpm, CPT I, and UCP-3 did not change significantly with either diet. CONCLUSIONS: A rapid and marked capacity for changes in dietary fatty acid availability to modulate the expression of mRNA-encoding proteins is necessary for fatty acid transport and oxidative metabolism. This finding is evidence of nutrient-gene interactions in human skeletal muscle.     

Effect of soy product kinako and fish oil on serum lipids and glucose metabolism in women with metabolic syndrome

ObjectivesAt the doses typically used to treat hypertriacylglycerolemia, fish oil may increase low-density lipoprotein (LDL) cholesterol and blood glucose levels. The aim of the present study was to verify whether soy could attenuate the effects of fish oil on blood lipids and carbohydrate metabolism in patients with metabolic syndrome.MethodsSixty-five women (47.9 ± 9.98 y) were studied with the use of a parallel, randomized design. The control group maintained the usual diet; the second group received 29.14 g/d of soy (kinako); the third group received 3 g/d of fish oil n-3 fatty acids; and the fourth group received fish oil (3 g/d) and kinako (29.14 g/d). Assessments were performed at baseline and after 45 and 90 d.ResultsIn relation to baseline values, fish oil increased (P < 0.05) total and LDL cholesterol, glucose, insulin, and homeostasis model assessment of insulin resistance levels after 90 d. Comparisons among groups demonstrated a decrease (P < 0.05) in total cholesterol in the fish oil and kinako group after 90 d as compared with the fish oil group. LDL cholesterol decreased (P < 0.01) in the kinako group as compared with the fish oil group. Blood glucose and homeostasis model assessment of insulin resistance levels decreased after 90 d (P < 0.01 and P < 0.05, respectively) and insulin levels decreased (P < 0.05) after 45 d when the kinako group was compared with the fish oil group.ConclusionsThe present study showed that kinako moderates the adverse effects of high doses of fish oil on LDL cholesterol, total cholesterol, and glucose metabolism levels.     

Influence of a low protein diet on serum transaminases,hepatic enzymes and lipid peroxidation in chloroquine treated rats

The influence of a low protein diet (3% protein) on serum transaminases, hepatic enzymes and the hepato-toxicity effect on lipid peroxidation of chloroquine consumption in rat liver was investigated. Rats fed with low protein diet (LPD) were orally treated with chloroquine (CQ) 5 mg/kg body wt for 8 weeks. Results showed that feeding rats with LPD for 8 weeks did not affect the responses of CQ to serum transaminases, while a remarkable increase in lactate dehydrogenase activity was observed. The protein contents of the liver homogenate showed a simultaneous decrease with the liver weights. This was accompanied by the reduction in NADPH-linked and ascorbate-linked lipid peroxidation. There was a decrease in hepatic acid phosphatase activity and a remarkable decrease in the total cholesterol liver. These results confirm the hypothesis that LPD may lead to dysfunction of the liver cells and thus interests in a way to modify the metabolism of CQ.     

大豆异黄酮对高胆固醇模型大鼠血清胆固醇浓度和肝脏胆固醇代谢的影响

目的观察大豆异黄酮对高脂模型大鼠血清胆固醇浓度及其肝脏胆固醇代谢关键酶基因表达的影响。方法 9周龄SD雄性大鼠8只喂饲AIN93M饲料（阴性对照组）,18只喂饲高脂饲料建立高胆固醇模型。14 d后将高胆固醇大鼠随机分为异黄酮组（每天灌胃360 mg/kg BW大豆异黄酮）和高脂对照组,喂饲高脂饲料至实验结束。30 d后测血脂,实时定量聚合酶链式反应（polymerase chain reaction,PCR）测定肝脏羟甲戊二酰辅酶A还原酶（3-hydroxy-3-methylglutaryl-Coenzyme A reductase,Hmgcr）、胆固醇7α-羟化酶（cytochrome P450,family 7,subfamily a,polypeptide 1,Cyp7a1）、低密度脂蛋白受体（low density lipoprotein receptor,Ldlr）mRNA表达量。结果异黄酮组大鼠血清总胆固醇（total cholesterol,TC）和低密度脂蛋白胆固醇（low density lipoprotein cholesterol,LDLC）浓度分别比高脂对照组降低了23.7%（q=2.79,P=0.010）和23.2%（q=2.63,P=0.015）;动物肝脏的Hmgcr和Cyp7a1 mRNA表达量均出现下降,但差异无统计学意义（均有P〉0.05）。结论大豆异黄酮可明显降低高胆固醇大鼠血清TC和LDLC浓度,有可能影响肝脏胆固醇代谢。     

Supplementation of soy protein with branched-chain amino acids alters protein metabolism in healthy elderly and even more in patients with chronic obstructive pulmonary disease

BACKGROUND: It is often suggested that chronic wasting diseases [eg, chronic obstructive pulmonary disease (COPD)] may benefit from branched-chain amino acid (BCAA) administration via improved protein metabolism. OBJECTIVE: The aim was to examine whether adding BCAAs to a soy protein meal would enhance protein anabolism in COPD patients and in healthy elderly persons. DESIGN: Eight normal-weight COPD patients and 8 healthy control subjects were examined on 2 test days. Simultaneous continuous intravenous infusion of l-[ring-(2)H(5)]phenylalanine (Phe) and l-[ring-(2)H(2)]tyrosine tracers was done postabsorptively and at 2 h of ingestion of a maltodextrin soy or maltodextrin soy + BCAA protein meal (rate of ingestion: 0.02 g protein.kg body weight(-1).20 min(-1)) in a crossover design. Together with the meal, oral ingestion of 1-[(13)C]Phe was performed to measure first-pass Phe splanchnic extraction (SPE(Phe)). The endogenous rate of Phe appearance [reflecting whole-body protein breakdown (WbPB)], whole-body protein synthesis (WbPS), and net WbPS (WbPS - WbPB) were calculated. Arterialized venous blood was sampled for amino acid enrichment and concentration analyses. RESULTS: Soy feeding induced a reduction in WbPB and an increase in WbPS. BCAA supplementation of soy protein resulted in a significantly higher (P < 0.05) increase in WbPS than did soy protein alone in COPD patients but not in the healthy elderly. BCAA supplementation did not significantly alter the change in WbPB or net WbPS. Furthermore, BCAA supplementation decreased (absolute) SPE(Phe) (P < 0.05) but did not change the percentage Phe hydroxylation in the splanchnic area, which indicates a BCAA-related reduction in splanchnic protein synthesis. CONCLUSION: BCAA supplementation to soy protein enhances WbPS in patients with COPD and alters interorgan protein metabolism in favor of the peripheral (muscle) compartment in healthy elderly and even more in COPD patients.     

Long-term intake of a high prebiotic fiber diet but not high protein reduces metabolic risk after a high fat challenge and uniquely alters gut microbiota and hepatic gene expression

A mismatch between early developmental diet and adulthood may increase obesity risk. Our objective was to determine the effects of re-matching rats to their weaning diets high in protein or fiber after transient high-fat/high-sucrose challenge in adulthood. We hypothesize that a long-term high fiber diet will be associated with a gut microbiota and hepatic gene expression reflective of reduced adiposity. Wistar rat pups were fed a control (C), high prebiotic fiber (HF), or high protein (HP) diet from 3–15 weeks of age; a high-fat/high-sucrose diet from 15–21 weeks; their respective C, HF, or HP diets from 21–25 weeks. Gut microbiota of cecal contents and hepatic gene expression were measured when rats were terminated at 25 weeks of age. HF rats had higher total bacteria, bifidobacteria and Bacteroides/Prevotella spp than C and HP at 25 weeks (P < 0.05). Firmicutes, especially Clostridium leptum, decreased in HF compared to C and HP (P < .05). The ratio of Firmicutes:Bacteroidetes was markedly lower in HF versus C and HP at 25 weeks (P < .05). HF decreased hepatic cholesterol content compared to HP and C at 25 weeks. HF and HP increased 3-hydroxy-3-methylglutaryl-CoA reductase mRNA and decreased lecithin-cholesterol acyltransferase mRNA compared to C (P < .05). In conclusion, re-matching rats to a HF but not HP diet attenuated the typical increase in Firmicutes:Bacteroidetes ratio associated with consumption of a high fat diet. Lower hepatic cholesterol with long-term HF diet intake may be related to alterations in gut microbiota and hepatic lipid metabolism.     

Effects of dietary protein on renal function and lipid metabolism in five-sixths nephrectomized rats

The objective of the present experiment was to examine the effect of substituting different quantities of soyabean protein for casein on renal function and lipid metabolism in rats with chronic renal failure induced by a five-sixths nephrectomy. Experimental animals were subjected to a nephrectomy and fed either casein or soyabean protein (200 or 100 g/kg diet). The diets were isoenergetic with identical fat, Na, K and P contents. Rats ingesting 200 g casein/kg diet showed a significantly (P<0.05) accelerated course of chronic renal failure, while the soyabean-protein groups showed retarded progression of the experimentally induced renal disease and hypercholesterolaemic effects. Rats in the low-soyabean-protein diet (100 g/kg) also demonstrated increased serum albumin and decreased serum triacylglycerol, total cholesterol concentrations and blood urea-N; however, the low-casein diet significantly (P<0.05) increased serum triacylglycerol. Results of the present study show that the replacement of casein by soyabean protein was related to the rate of progression of renal failure and improvement in lipid profiles in serum of five-sixths nephrectomized rats.     

Soy protein and fish oil independently decrease serum lipid concentrations but interactively reduce hepatic enzymatic activity and gene expression involved in fatty acid synthesis in rats

The degree of interaction between dietary protein and fat sources to modulate hepatic lipid metabolism was investigated. Male rats were fed diets containing either casein or soy protein isolate as the protein source and either palm or soy oil as the fat source. After 3 wk, the activity and mRNA expression of enzymes involved in hepatic fatty acid synthesis were significantly lower with soy protein than casein when palm oil was the fat source. The same values for the same enzymes were greatly lowered regardless of the protein source when fish oil was the fat source. Both enzymatic activity and mRNA expression for fatty acid oxidation were significantly stimulated by fish oil, but only the former was increased by soy protein. Although both soy protein and fish oil reduced serum lipid concentrations, they worked independently. In soy protein-fed rats, mRNA levels of key enzymes related to cholesterol and bile acid synthesis were decreased and increased, respectively, compared with levels in casein-fed animals. Instead, fish oil strongly induced the mRNA expression of biliary cholesterol transporters, ATP-binding cassette sub-family G, member 5 (ABCG5) and ATP-binding cassette sub-family G, member 8 (ABCG8). Therefore, dietary soy protein and fish oil generally exerted independent hypolipidemic actions in rats. However, the reduction of hepatic fatty acid synthesis caused by the simultaneous ingestion of soy protein and fish oil was smaller than their expected additive reduction, because fish oil strongly decreased the synthesis.     

Dietary beta-carotene reduces serum lipid concentrations in spontaneously hypertensive rats fed a vitamin A-fortified and cholesterol-enriched diet.

The effects of dietary beta-carotene on serum lipid concentrations were examined in spontaneously hypertensive (SH) rats. Groups of SH rats were fed a semipurified, vitamin A-fortified and cholesterol-enriched diet supplemented with 0, 125, 250 or 500 mg beta-carotene/kg diet for a period of 44 d. beta-Carotene supplementation resulted in significant dose-related decreases in serum total, LDL and HDL cholesterol concentrations and serum total, VLDL and LDL triacylglycerol concentrations. The ratio of HDL cholesterol to total cholesterol was unchanged or slightly increased by dietary beta-carotene. The study suggests that dietary beta-carotene has antihyperlipidemic effects in SH rats. The effects in humans and the mechanism of the effects remain to be investigated.     

Soy protein affects serum insulin and hepatic SREBP-1 mRNA and reduces fatty liver in rats

The consumption of soy protein was shown to reduce blood lipids in humans and other animal species. Furthermore, it was shown that the ingestion of soy protein maintains normal insulinemia. Thus, the purpose of the present study was to determine whether soy protein affects the synthesis of lipids in the liver through sterol-regulatory element binding protein-1 (SREBP-1) due to modulation of insulin levels. We first conducted a short-term study in which rats were fed a diet containing 18 g/100 g soy protein or casein for 10 d. Rats fed soy protein had significantly lower serum insulin concentrations than rats fed casein, and this response was accompanied by an elevation in hepatic SREBP-1 mRNA that was 53% lower than that in rats fed casein at d 10. The increase in SREBP-1 mRNA occurred 30 min after consumption of the casein mean, and increased steadily for the next 2 h. We then conducted a second study to assess the long-term effect of soy protein consumption for 150 d on hepatic SREBP-1 expression. Long-term consumption of soy protein maintained normal insulin concentrations compared with rats fed casein, which were hyperinsulinemic. Thus, rats fed the soy protein diet had significantly lower expression of SREBP-1 mRNA than rats fed the casein diet. Soy protein intake also reduced the expression of fatty acid synthase (FAS) and malic enzyme, leading to low hepatic lipid depots of triglycerides and cholesterol, whereas rats fed the casein diet developed fatty liver. These data suggest that soy protein regulates SREBP-1 expression by modulating serum insulin concentration, thus preventing the development of fatty liver.     

Isolated soy protein consumption reduces urinary albumin excretion and improves the serum lipid profile in men with type 2 diabetes mellitus and nephropathy

Soy protein was shown to exhibit several beneficial effects on renal function in nondiabetic patients with nephropathy, and to improve serum lipids. This study examined the effects of isolated soy protein consumption on urinary albumin excretion, serum lipids, plasma amino acids, and isoflavones in diabetic patients with nephropathy. Male patients (n = 14) with type 2 diabetes and nephropathy were followed in a crossover design for 7 mo. The study comprised two 8-wk intervention periods, placed between a 4-wk lead-in and two 4-wk washout periods. In the 2 intervention periods, 0.5 g/(kg. d) of the dietary protein was provided as either isolated soy protein (ISP) or casein, in random order. Blood and urine samples were collected at the beginning and end of each period. Data were analyzed by multiple linear regression for a repeated-measure design. ISP consumption led to changes of -9.5% in urinary albumin excretion (P < 0.0001), -0.45 in the total-to-HDL-cholesterol ratio (P < 0.05), -0.20 in the LDL-to-HDL cholesterol ratio (P < 0.05), and +4.3% in HDL cholesterol (P = 0.0040). Plasma arginine concentrations, the arginine-to-lysine ratio, and plasma isoflavone concentrations were higher after ISP consumption (P < 0.05). Urinary albumin excretion was negatively correlated with plasma total isoflavones (rho = -0.441), daidzein (rho = -0.326), and O-desmethylangolesin (rho = -0.389) (P < 0.05). The findings indicate that isolated soy protein consumption improves several markers that may be beneficial for type 2 diabetic patients with nephropathy.     

Studies dealing with hepatic RNA metabolism in rats force-fed a threonine-devoid diet

Young rats were force-fed for 3 days a purified diet devoid of threonine and a number of aspects relating to RNA metabolism in the livers were studied. The findings in the livers of rats force-fed the threonine-devoid diet in comparison with those force-fed the complete diet were as follows: a) poly(A)-mRNA was increased in nuclei and in polyribosomes; b) DNA-dependent RNA polymerases I and II activities were increased; c) in vitro release of 14C-orotic acid labeled RNA from nuclei revealed that transport was unchanged and nucleoside triphosphatase activity of nuclear envelopes was unchanged; d) polyribosomes (total, free and membrane-bound) shifted toward heavier aggregation and in vitro 14C-leucine incorporation into protein was increased; e) RNase activities (at pH 5.4, 7.6, 9.5) were essentially unaltered; and f) in vivo 14C-choline incorporation into microsomal membranes was increased. By administering selected inhibitors of RNA and protein synthesis, such as actinomycin D, alpha-amanitin or cycloheximide, prior to killing the rats force-fed the threonine-devoid or complete diet for 3 days, it was demonstrated that the stimulatory effect on hepatic polyribosomes and protein synthesis in the experimental group was dependent upon new synthesis of poly(A)mRNA and of protein.