Excretion Of Acidic Steroids Research Articles

Identification of a novel cholesterol-lowering dipeptide, phenylalanine-proline (FP), and its down-regulation of intestinal ABCA1 in hypercholesterolemic rats and Caco-2 cells

There has been no report about in vivo active cholesterol-lowering dipeptide in any protein origin, despite their potential health benefits. Cattle heart protein hydrolysate ultra-filtrate (HPHU, molecular weight < ca. 1,000 Da peptide mixture) exhibits cholesterol-lowering activity in hypercholesterolemic rats, but the active peptide in HPHU that lowers serum cholesterol levels and its molecular mechanism are unknown. In this study, we separated and purified HPHU to identify a novel cholesterol-lowering dipeptide (phenylalanine-proline, FP) and characterized the mechanism underlying its effects in vivo and in vitro. We identified FP as an active peptide from HPHU by MALDI-TOF mass spectrometry. FP significantly decreased serum total and non-HDL cholesterol and hepatic cholesterol levels in rats. FP significantly increased serum HDL cholesterol, accompanied by a significant decrease in the atherogenic index. FP also significantly increased fecal cholesterol and acidic steroid excretion. Moreover, FP significantly decreased ATP-binding cassette transporter A1 (ABCA1) expression in the rat jejunum and reduced cholesterol absorption in Caco-2 cells. We found a novel cholesterol-lowering dipeptide FP that could improve cholesterol metabolism via the down-regulation of intestinal ABCA1. The cholesterol-lowering action induced by FP was disappeared in PepT1KO mice. FP-induced cholesterol-lowering action is mediated via PepT1 in mice.

Modified Soybean Affects Cholesterol Metabolism in Rats Similarly to a Commercial Cultivar

The consumption of soy protein lowers blood cholesterol in humans and animals. Breeding may alter the physiological effects of soybeans, such as its cholesterol-lowering property. Our hypothesis is that breeding affects the hypocholesterolemic effect of soy by modulating the expression of key hepatic enzymes related to cholesterol and bile acid biosynthesis, as well as altering fecal neutral and acidic steroid excretion. Therefore the aim of this study was to evaluate the effect of a new Brazilian soybean cultivar (UFV-116), lacking lipoxygenases 2 and 3, compared with a commercial cultivar (OCEPAR-19), on 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) and cholesterol 7α-hydroxylase (CYP7A) mRNA expression and fecal steroid output in rats. Thirty-six male rats were fed UFV-116, OCEPAR-19, or casein as the protein source, with or without addition of dietary cholesterol (0.25%). Blood and liver cholesterol, HMGR and CYP7A mRNA abundance, and fecal excretion of steroids were measured. Blood and liver cholesterol levels were lowered by both soybean cultivars, with and without cholesterol, but UFV-116 was more effective when included in the cholesterol-free diet. Both soy diets promoted lower levels of HMGR mRNA, higher levels of CYP7A mRNA, and higher excretion of fecal secondary bile acids. There was higher fecal neutral steroid output when cholesterol was added to all diets. These data show that both soybean cultivars acted similarly in lowering serum and hepatic cholesterol; therefore, breeding did not affect the hypocholesterolemic effect of the new cultivar.

Cholesterol-Lowering Effect of Black Tea Polyphenols, Theaflavins, Theasinensin A and Thearubigins, in Rats Fed High Fat Diet

Rats were fed a high fat diet containing 0.2% black tea polyphenols, theaflavins, theasinensin A or thearubigins for 4 weeks. The hepatic cholesterol concentration was significantly lower in rats fed the theaflavins, theasinensin A or thearubigins diet than in those fed the control diet without black tea polyphenols. Theasinensin A and thearubigins significantly accelerated fecal neutral and acidic steroid excretion, respectively. These results suggest that theasinensin A and thearubigins might induce the hepatic cholesterol-lowering activity through the promotion of fecal steroid excretion.

麦類に含まれる食物繊維の栄養生理学的研究

Oats and barley are rich in water-soluble dietary fiber which is mainly composed of β-glucan. This study evaluates the nutritional and physiological effects of the water-soluble dietary fiber, cereal gum, in oats and barley from animal and human experiments.Effect of the water-soluble dietary fiber in oats and barley on the lipid metabolism in ratsThe effects of ingested oat and barley gum on the plasma and liver lipid levels were examined in genetically obese and lean Zucker rats. Obese and lean male Zucker rats, aged 6 weeks, were fed for 34 days on a standard diet or on diets corresponding to 2% total dietary fiber. Both the oat and barley gum suppressed the liver lipid accumulation and elevation of the plasma cholesterol level in obese rats. The results of this animal experiment indicate that ingested oat and barley gum ameliorated fatty liver and hypercholesterolemia in obese Zucker rats.Effects of oat and barley gum on the lipid metabolism in ratsThe effect of various amounts of oat and barley gum added to the diet on the plasma and liver lipid levels was examined in cholesterol-fed rats. Male Sprague-Dawley rats, aged 5 weeks, were fed for 9 days on a diet containing the oat or barley gum corresponding to 0%, 1%, 2%, or 4% soluble fiber. The plasma triglyceride, liver cholesterol, and liver triglyceride levels were lower in the rats fed on the diets containing 1-4% oat gum and 2-4% barley gum than in the rats fed on the gum-free diet. The diet containing 4% oat gum increased the fecal excretion of total lipids. The fecal excretion of acidic steroids was higher from the rats fed on the diets containing 2-4% oat gum and 1% barley gum than from the rats fed on the gum-free diet. The results of this experiment indicate that the minimum amounts of oat and barley gum, which acted as lipid-lowering compounds, were respectively 1% and 2% of fiber in the diet.Effect of oatmeal supplementation on the serum cholesterol levels in men with boundary and mild hypercholesterolemiaWe examined the effect of oatmeal containing β-glucan on blood lipids and the safety of its long-term intake in men with boundary and hypercholesterolemia. A total of 48 men with boundary and mild hypercholesterolemia were assigned to three groups. Each group A subject was given four pieces of placebo cookies once a day for 12 weeks, each group B subject was given test oatmeal cookies containing oatmeal at 30g/4 pieces, and each group C subject was given the same cookies containing oatmeal at 45g/4 pieces. The serum total cholesterol level for group C with boundary hypercholesterolemia was significantly lower than that for group A or group C (p<0.05). The results of this human trial indicate that supplementation with oatmeal at 45g/day (1.6g of β-glucan/day) decreased the serum total cholesterol level in men with boundary hypercholesterolemia.Additional human trial with oatmeal porridgeAn additional human trial with oatmeal porridge was examined; each subject in the oatmeal group was given oatmeal porridge containing 45g of oatmeal (1.6g of β-glucan) once a day for 12 weeks, and the control group subjects were given control porridge containing white rice and cellulose as the substitute for oatmeal. The level of serum total cholesterol in the oatmeal group was significantly lower than that in the control group throughout the ingestion period (p<0.05). This additional human trial indicates that oatmeal containing β-glucan could modulate the level of serum total cholesterol.Effect of oatmeal supplementation on the serum cholesterol levels in adults with boundary and mild hypercholesterolemiaThis study examined the effect of oatmeal on the serum cholesterol levels in Japanese adult men and women with boundary and mild hypercholesterolemia. Seventy-four men and nineteen women were randomly assigned to either the placebo or oatmeal group for

Absorption of Dietary Cholesterol Oxidation Products and Their Downstream Metabolic Effects Are Reduced by Dietary Apple Polyphenols

Exogenous and endogenous cholesterol oxidation products (COPs) perturb various metabolic processes, and thereby they may induce various homeostasis-related disorders. Here, we observed that procyanidin-rich dietary apple polyphenol (APP) from unripe apples alleviates the perturbation of lipid metabolism by decreasing the exogenous COP levels in rats. Dietary COPs may be the greatest source of COPs found in the human body. Rats (4 weeks of age) were fed AIN-purified diets containing 0.3% COPs supplemented with 0.5 or 2.5% APP for 3 weeks. Dietary APP alleviated the growth inhibition action of the exogenous COPs. The modulations of the liver lipid profile by COPs remained unchanged. However, serum total cholesterol, high-density lipoprotein cholesterol, and triglyceride levels increased following the intake of dietary APP. Further, dietary APP inhibited the increase in lipid peroxide levels in the liver and serum by COPs. The activity of hepatic Delta6 desaturase was lowered by dietary APP in a dose-dependent manner, although exogenous COPs generally increased the activity of this enzyme. In keeping with this observation, Delta6 desaturation indices in the phospholipids and cholesteryl esters of the liver and serum lipids were lower in the APP-fed groups than those in the control group. Dietary APP also promoted the excretion of exogenous COPs, cholesterol, and acidic steroids in feces. Therefore, the inhibition of intestinal absorption of COPs may partly contribute to the alleviation of the perturbation of lipid metabolism and lipid peroxidation levels. Thus, APP may be an important removal agent of exogenous toxic material such as COPs contained in processed or fast foods.

High protein buckwheat flour suppresses hypercholesterolemia in rats and gallstone formation in mice by hypercholesterolemic diet and body fat in rats because of its low protein digestibility

Objective This study evaluated the physiologic properties of high protein buckwheat flour (PBF) by examining its effects on serum cholesterol and body fat in rats and on cholesterol gallstone formation in mice. Methods Animals were fed experimental diets that contained casein, buckwheat protein extract (BWP), or PBF as a protein source (net protein content 200 g/kg). Results In experiment 1, consumption of PBF and BWP for 10 d caused 33% and 31% decreases, respectively, in serum cholesterol of rats fed cholesterol-enriched diets when compared with consumption of casein ( P < 0.05). Dietary PBF caused a significant decrease in liver cholesterol, whereas dietary BWP caused only a slight decrease ( P > 0.05). Fecal excretion of neutral and acidic steroids in the PBF group was significantly higher than those in the BWP and casein groups. In experiment 2, consumption of PBF for 10 d significantly suppressed adipose tissue weight and hepatic activity of fatty acid synthase in rats fed cholesterol-free diets compared with consumption of casein ( P < 0.05), whereas that of BWP for this period caused only a slight decrease in adipose tissue weight ( P > 0.05). In experiment 3, dietary PBF and BWP significantly decreased the incidence of cholesterol gallstones and lithogenic index in mice fed cholesterol-enriched diets for 27 d, which was associated with increased fecal excretion of acidic steroids. Conclusion This study demonstrated that PBF has strong activities against hypercholesterolemia, obesity, and gallstone formation, suggesting a potential usefulness of PBF as functional ingredient.

Dose‐dependent hypocholesterolemic actions of dietary apple polyphenol in rats fed cholesterol

The dose-dependent hypocholesterolemic and antiatherogenic effects of dietary apple polyphenol (AP) from unripe apple, which contains approximately 85% catechin oligomers (procyanidins), were examined in male Sprague-Dawley rats (4 wk of age) given a purified diet containing 0.5% cholesterol. Dietary AP at 0.5 and 1.0% levels significantly decreased the liver cholesterol level compared with that in the control (AP-free diet-fed) group. Dietary AP also significantly lowered the serum cholesterol level compared with that in the control group. However, the HDL cholesterol level was significantly higher in the 1.0% AP-fed group than in the control group. Accordingly, the ratio of HDL-cholesterol/total cholesterol was significantly higher in the 0.5% AP-fed group and 1.0% AP-fed group than in the control group. Moreover, the atherogenic indices in the 0.5 and 1.0% AP-fed groups were significantly lower than those in the control group. The activity of hepatic cholesterol 7alpha-hydroxylase tended to be increased by dietary AP in a dose-dependent manner. In accord with this observation, dietary AP increased the excretion of acidic steroids in feces. Dietary AP also significantly promoted the fecal excretion of neutral steroids in a dose-dependent manner. These observations suggest that dietary AP at a 0.5 or 1.0% level exerts hypocholesterolemic and antiatherogenic effects through the promotion of cholesterol catabolism and inhibition of intestinal absorption of cholesterol.

Effects of feeding oyster, Crassostrea gigas, on serum and liver lipid levels in rats.

The effects of feeding dietary and defatted oyster meat on lipid metabolism were investigated in rats by comparing measurements with those of casein and soybean protein. In the first experiment, male rats were fed 0.1% and 1% cholesterol-supplemented diets containing casein, oyster or soybean protein under the same dietary level of protein (20%). The concentrations of serum and liver cholesterol in the oyster group were significantly lower than those in the casein group for both the 0.1% and 1% cholesterol-supplemented diets. The cholesterol-lowering effect of oyster meat was more predominant than that of soybean protein. Feeding oyster meat significantly decreased the serum triglyceride concentration as compared to feeding casein for the 0.1% cholesterol-supplemented diets, and it reduced hepatic triglyceride concentration in both groups fed the 0.1% and 1% cholesterol-supplemented diets. The excretion of fecal total steroids was higher in the rats fed oyster meat than those fed casein or soybean protein for both the 0.1% and 1% cholesterol-supplemented diets. In the second experiment, the effects of defatted oyster on lipid metabolism were compared with casein and soybean protein in diets supplemented with cholesterol. The serum cholesterol concentration in the defatted oyster group was comparable to that in the other two groups, but the ratio of high-density lipoprotein-cholesterol to total cholesterol was higher in the defatted oyster group. The feeding of defatted oyster induced a lower liver cholesterol concentration as compared to casein and soybean protein. Serum and liver triglyceride levels were lower in the defatted oyster group than in the casein group. Defatted oyster accelerated the fecal excretion of both neutral and acidic steroids as compared to casein. Our results suggest that the feeding of oysters exerts a more potent hypolipidemic activity than soybean protein, and the effect may be ascribed to both lipid and non-lipid fractions in oyster.

Hypocholesterolemic effect of Lactobacillus gasseri SBT0270 in rats fed a cholesterol-enriched diet.

The effects of administration of Lactobacillus gasseri SBT0270 on serum lipids and bile acids, faecal bile acids and microflora were estimated in hypercholesterolemic rats. An effective dose of strain SBT0270 to exert its hypocholesterolemic effect was 10(9) viable cells/d. The dose of 10(9) cells/d did not affect the faecal coliform counts, but the number of faecal lactobacilli in rats fed this dose was significantly higher than that in the control group observed at the end of feeding period. Hypocholesterolemic effect of Lb. gasseri SBT0270 was attributed to its ability to suppress the reabsorption of bile acids into the enterohepatic circulation and to enhance the excretion of acidic steroids in faeces of hypercholesterolemic rats.

Stronger suppression of plasma cholesterol and enhancement of the fecal excretion of steroids by a buckwheat protein product than by a soy protein isolate in rats fed on a cholesterol-free diet.

We investigated the effects of a buckwheat protein product (BWP), soy protein isolate (SPI) and casein on the plasma cholesterol level and fecal steroid excretion in rats fed on a cholesterol-free diet. The consumption of BWP suppressed plasma cholesterol by enhancing the fecal excretion of both neutral and acidic steroids. These effects of BWP were stronger than those of SPI.

Effect of Administration of Lactobacillus gasseri on Serum Lipids and Fecal Steroids in Hypercholesterolemic Rats

The effects of milk and nonfermented milks produced from Lactobacillus gasseri on serum lipids and total bile acids and fecal steroids and microflora were estimated in rats fed cholesterol-enriched diets. Lactobacilli decreased and coliforms increased in feces of the control group; however, the concentrations of fecal lactobacilli remained unchanged when rats were fed non-fermented milks. Fecal coliforms in rats receiving milk and nonfermented milk produced from L. gasseri SBT0270 increased, while rats receiving nonfermented milk produced from L. gasseri SBT0274 had lower fecal coliform count than did the control group. Only NFM-A significantly reduced serum total cholesterol and low-density lipoprotein (LDL) cholesterol, and bile acids. High-density lipoprotein (HDL) cholesterol was significantly decreased when rats were given milk and nonfermented milks. Milk and NFM-A lowered serum triglycerides levels. Milk and nonfermented milks did not affect the total neutral steroids, but higher levels of acidic steroid were detected in the feces than the control group. The results showed that the hypocholesterolemic effect of L. gasseri SBT0270 was attributed to its ability to suppress the reabsorption of bile acids into the enterohepatic circulation and to enhance the excretion of acidic steroids in feces of hypercholesterolemic rats.

A Buckwheat Protein Product Suppresses Gallstone Formation and Plasma Cholesterol More Strongly than Soy Protein Isolate in Hamsters

This study was conducted to investigate the effects of a buckwheat protein product (BWP) on plasma cholesterol, gallbladder bile composition and fecal steroid excretion in hamsters fed diets with 5 g/kg cholesterol. Diets also contained 200 g/kg of casein, soy protein isolate (SPI) or BWP as protein sources. After 2 wk, plasma and liver concentrations of cholesterol in the hamsters fed BWP were significantly lower than those in the hamsters fed casein and SPI. The molar proportion of cholesterol in gallbladder bile was significantly lower in the BWP group than in the other groups, whereas that of bile acids was slightly higher in the BWP group (P </= 0.05), resulting in the lowest lithogenic index in the BWP group. None of the hamsters fed BWP had gallstones, whereas they were present in some of the hamsters fed other proteins. Compared with casein intake, BWP intake resulted in significantly higher ratios of cholic acid to chenodeoxycholic acid and of cholic acid to lithocholic acid in the gallbladder bile. The excretions of fecal neutral and acidic steroids were markedly higher in the BWP group compared with the other groups (P </= 0.05). SPI intake also significantly lowered cholesterol level in gallbladder bile and caused higher fecal bile acids compared with casein intake, but the effects were significantly less than those of BWP (P </= 0.05). The results suggest that BWP suppresses gallstone formation and cholesterol level more strongly than SPI by enhancing bile acid synthesis and fecal excretion of both neutral and acidic steroids.

Dietary oxidized cholesterol modulates cholesterol metabolism and linoleic acid desaturation in rats fed high-cholesterol diets.

The interactive effect of high dietary levels of oxidized cholesterol on exogenous cholesterol and linoleic acid metabolism was examined in male 4-wk-old Sprague-Dawley rats given high-cholesterol diets. The rats were pair-fed purified diets free of or containing either 0.5% cholesterol alone or both 0.5% cholesterol and 0.5% oxidized cholesterol mixture (containing 93% oxidized cholesterol) for 3 wk. Hepatic 3-hydroxy-3-methylglutaryl CoA reductase activity was reduced in rats given cholesterol alone or both cholesterol and oxidized cholesterol. However, hepatic cholesterol 7alpha-hydroxylase activity was lowered only when rats were given both cholesterol and oxidized cholesterol, although dietary cholesterol increased this activity. Reflecting this effect, acidic steroid excretion was lowest among the groups of rats given cholesterol and oxidized cholesterol. On the other hand, the activity of hepatic delta6 desaturase, a key enzyme in the metabolism of linoleic acid to arachidonic acid, was increased in rats given both cholesterol and oxidized cholesterol, although dietary cholesterol alone lowered its activity. As a result, the delta6 desaturation index, 20:3n-6 + 20:4n-6/18:2n-6, in liver and serum phospholipids tended to be higher in the group fed both cholesterol and oxidized cholesterol than in the one fed cholesterol alone. Thus, dietary oxidized cholesterol significantly modulated exogenous cholesterol metabolism and promoted linoleic acid desaturation even when it was given at high levels together with a high cholesterol diet.

Highly Purified Soybean Protein Is Not Hypocholesterolemic in Rats but Stimulates Cholesterol Synthesis and Excretion and Reduces Polyunsaturated Fatty Acid Biosynthesis

The specific effects of soybean protein on lipid metabolism were determined with highly purified soybean protein. At 5 wk of age, growing rats were fed diets containing 20% highly purified soybean protein or casein supplemented or not with 0.1% cholesterol for 2 mo. Plasma and liver lipid composition, fecal steroid excretion and several hepatic enzyme activities were measured. There were no significant dietary protein-related differences in plasma and liver cholesterol concentrations. When diets were cholesterol free, highly purified soybean protein stimulated fecal neutral and acidic steroid excretion associated with concomitantly higher hydroxy methylglutaryl CoA (HMG-CoA) reductase activity, but lower cholesterol 7α-hydroxylase activity. Soybean protein lowered the linoleate desaturation index [20:4(n-6)/18:2(n-6)] in liver microsomal lipids and phospholipids. This may have been due to the reduced microsomal Δ6(n-6) desaturase activity in rats fed soybean protein, whereas Δ5(n-6) desaturase activity did not differ between groups fed the two proteins. Cholesterol supplementation (0.1%) did not affect plasma cholesterol but increased liver cholesterol and triacylglycerol concentrations and reduced HMG-CoA reductase activity; this latter effect was greatest in rats fed soybean protein. Cholesterol 7α-hydroxylase activity, however, was diminished only in rats fed casein. Desaturase activities, and particularly Δ5(n-6) activity, were lowered by cholesterol supplementation in rats fed both protein diets, including a significantly lower 20:4(n-6)/18:2(n-6) ratio in liver microsomal lipids and liver phospholipids. Thus although dietary proteins have no effect on serum cholesterol in rats, they affect enzyme activities involved in cholesterol metabolism and fatty acid desaturation.

Absorption, excretion, and distribution of plant sterols after proximal gut resection and autotransplantation of porcine ileum.

Contribution of different gut segments to plant sterol absorption, adaptation of plant sterol absorption after partial small bowel resection, and effects of gut transplantation (necessitates extrinsic autonomic denervation and lymphatic disruption) on plant sterol biodynamics are unclear. We studied the consequences of massive proximal small bowel resection and autotransplantation of the remaining ileum on the adaptive absorption and biodynamics of plant sterols. Dietary, fecal, biliary, hepatic and plasma plant sterols, fecal elimination and absorption of cholesterol, small bowel morphology, and intestinal transit were determined before (n = 5) and at 4, 8, and 14 wk after resection of the proximal 75% of the jejunoileum (n = 15) and autotransplantation of the remaining ileum (n = 15) or transection (n = 5). Proximal gut resection significantly reduced cholesterol absorption efficiency; percentage absorption and biliary secretion of plant sterols; plasma, biliary and hepatic campesterol-to-cholesterol proportions; and sitosterol proportions in plasma and bile. Autotransplantation of the remaining ileum further significantly decreased cholesterol absorption efficiency; percentage absorption and biliary secretion of campesterol; campesterol proportions in plasma, bile and liver; and plasma proportions of sitosterol while increasing fecal excretion of neutral and acidic steroids. Plasma proportions of the two plant sterols, but absorption of just campesterol, were gradually improved with increasing cholesterol absorption and villus height after proximal gut resection; the same result was observed to a lesser degree after ileal autotransplantation. In addition, significant positive correlations were found between percentage cholesterol and campesterol absorption and the plasma plant sterol proportions in both proximal resection groups, between campesterol absorption and ileal villus height in the resection group, and between campesterol absorption and intestinal transit time in the autotransplantation group. In conclusion, plasma campesterol and sitosterol closely reflect absorption of cholesterol and plant sterols from intact and autotransplanted ileum during adaptation to proximal gut resection. A loss of proximal gut absorptive surface impairs cholesterol and campesterol absorption more than sitosterol absorption, the latter being apparently less dependent on available jejunal villus surface area.

Soybean protein lowers serum cholesterol levels in hamsters: Effect of debittered undigested fraction

the undigested fraction (UDF) of soybean protein exerts a marked hypocholesterolemic effect in relation to soybean protein (SOY) in rats. The present study was conducted to confirm whether UDF was effective in hamsters as in rats in combination with different fat sources, either perilla oil (PER) or safflower oil (SAF). Because the hamster, unlike the rat, disliked the bitter taste of UDF, the effect of debittering UDF also was studied. Cholesterol-enriched (0.2%) diets containing 20% protein and 10% fat were fed to hamsters for 4 wk. UDF was more hypocholesterolemic than soybean protein in hamsters regardless of the dietary fat source. The ratio of high-density lipoprotein to total cholesterol essentially remained unchanged. The debittered UDF, without influencing food intake and thereby weight gain, exerted a significant hypocholesterolemic effect comparable with UDF in relation to SOY accompanying stimulation of fecal neutral and acidic steroid excretion. The fatty acid composition of liver phospholipids was influenced by the type of the dietary protein, and both UDF seemed to interfere characteristically more than SOY with the desaturation systems between linoleic acid and arachidonic acid. Thus, the debittered UDF, similar to UDF, exerted a distinct influence on the various parameters of lipid metabolism in relation to SOY.

ABSORPTION AND LYMPHATIC TRANSPORT OF INTERESTERIFIED OR MIXED FATS RICH IN SATURATED FATTY ACIDS AND THEIR EFFECT ON TISSUE LIPIDS IN RATS

Interesterification of fully hydrogenated plant oils with liquid oils has been used as an alternative to partial hydrogenation to produce a zero-trans solid fat due to recent reports of unfavorable effects of dietary trans fatty acids on serum cholesterol levels. Present study was carried out to examine absorption of saturated fatty acids derived from mixed and interesterified fats and their effects on concentration of serum cholesterol. Dietary fats consisted of tripalmitin or tristearin: high oleic safflower oil: safflower oil ratios of 44.4:35.3:20.3 or their interesterified products; a melting point of the interesterified fat was lower than that of the corresponding mixed fats. When rats were fed these-fat containing diets for three wks, absorption rate estimated by excretion of fatty acids into feces was higher in interesterified fat-fed rats than in the corresponding mixed fat-fed rats. This improved absorption was accompanied by an increased concentration of liver triacylglycerols and an increased proportion of stearic acid in the adipose tissue and an increased proportion of oleic acid in serum and liver. Dietary fats exerted no significant effect on the liver or serum cholesterol concentration or the excretion of neutral or acidic steroids into feces. In contrast to dietary fat absorption, administration of the mixed and interesterified fats, emulsified with taurocholate and albumin, into stomach of rats cannulated with thoracic lymph duct resulted in lymphatic triacylglycerols with a comparable transport rate and with a similar fatty acid composition at each position of triacylglycerols. These results demonstrate that interesterification improves absorption of dietary fats, possibly by facilitating emulsification of saturated fats, but seems not to exert any adverse effects on the concentration of serum and liver cholesterol. © 1997 Elsevier Science Inc.

Effect of ileal autotransplantation on cholesterol, bile acids, and biliary lipids in pigs with proximal small bowel resection

Our major aim was to investigate the consequences of ileal autotransplantation in pigs with proximal small intestinal resection on biliary lipids and metabolism of bile acids. Biliary lipid secretion rates and bile acid absorption were assessed by measuring dietary and biliary lipids, fractional cholesterol absorption, and fecal excretion of cholesterol and bile acids. In addition, serum bile acids and cholesterol, biliary and fecal bile acid species, and ileal villus height were determined after resection of the proximal 75% of the jejunoileum (n = 15) and autotransplantation of the remaining ileum with systemic venous drainage (n = 15) or transection (n = 5). Autotransplantation further increased fecal excretion of neutral and acidic steroids and serum concentration of bile acids after proximal resection (P < .05 for all); autotransplantation significantly decreased serum cholesterol, ileal villus height, fractional bile acid and cholesterol absorption, and biliary molar percentage of total and primary bile acids, whereas biliary secretion of bile acids, enriched by secondary bile acids, and cholesterol remained unchanged. At 14 weeks, ileal villus height, fractional bile acid and cholesterol absorption, biliary molar percentage of bile acids, and proportion of secondary biliary bile acids were altered by transplantation from the respective postresection values of 864 +/- 22 microm, 97.9 +/- 0.6%, 26.9 +/- 3.9%, 91.8 +/- 1.2% and 9.2 +/- 1.3% to 428 +/- 21 microm, 91.1 +/- 1.5%, 9.5 +/- 1.1%, 83.9 +/- 1.4% and 52.5 +/- 3.5% (P < .005 for all). Posttransplantation biliary bile acid secretion correlated positively with fractional reabsorption (r = .70) and biliary molar percentage (r = .73) of bile acids and ileal villus height (r = .65; P < .01 for all). Decreased absorption efficiency and biliary molar percentage of bile acids, increased biliary secondary bile acids, and short ileal villi point to bacterial overgrowth-induced bile acid malabsorption, which with decreased absorptive area may contribute to malabsorption of other lipids after ileal autotransplantation. Compensatory increase in cholesterol synthesis in the pigs with autotransplanted ileum appeared sufficient for constant biliary secretion of cholesterol and bile acids.

Dietary safflower phospholipid reduces liver lipids in laying hens

This experiment was conducted to determine the effects of dietary safflower phospholipids (crude safflower phospholipid and purified safflower phospholipid) on performance and lipid metabolism of laying hens. Sixty-week-old Single Comb White Leghorn laying hens were divided into four groups of seven birds each, and were given one of four experimental diets containing 5% beef tallow (served as a control, tallow), a mixture of safflower oil and palm oil (SP-oil), crude safflower phospholipid (Saf-PLcrude), or purified safflower phospholipid (Saf-PL) for 7 wk. Egg production ratio and daily egg mass were significantly higher in hens fed Saf-PLcrude diets than in hens of the other diet groups. There were no significant differences in egg weight among groups. Liver cholesterol and triglyceride contents were significantly decreased in all treated groups as compared with the control. The activity of hepatic 3-hydroxy-3 methylglutaryl coenzyme A reductase was the highest in hens fed the Saf-PLcrude diet. Serum esterified cholesterol concentration was decreased by feeding of SP-oil, Saf-PLcrude, or Saf-PL diets. Serum lecithin-cholesterol acyltransferase activity was highest in hens fed the tallow diet. Excreta neutral steroid excretion was significantly increased in the Saf-PLcrude or Saf-PL diet groups, although acidic steroid excretion was not affected by dietary treatments. Total cholesterol, triglyceride, and phospholipid contents in egg yolks were not different for any dietary treatments. The fatty acid compositions of egg yolks from hens fed Saf-PLcrude diets were not different with those fed the SP-oil diet, although eggs of hens fed the Saf-PL diet showed lower total polyunsaturated fatty acids. These results suggest that dietary safflower phospholipids may be a valuable ingredient to layers for reducing liver triglycerides and serum cholesterol without any adverse effects.

Additive hypocholesterolemic effect of psyllium and cholestyramine in the hamster: influence on fecal sterol and bile acid profiles

Recent findings suggest that the effects of cholestyramine and psyllium in combination could be additive for cholesterol-lowering. We therefore examined the effect of both agents, alone and in combination, on lipoprotein cholesterol and neutral and acidic steroid excretion in the hamster. Animals (n = 8/group) were fed for 21 days, either a basal chow diet supplemented with 10% palm oil and 0.2% cholesterol, or one of four treatments consisting of the basal diet plus: 5.5% cellulose; 5% psyllium with 0.5% cellulose; 0.5% cholestyramine with 5% cellulose; or 5% psyllium with 0.5% cholestyramine. Psyllium and cholestyramine both had significant hypocholesterolemic effects, but in combination produced additive reductions in lipoprotein and hepatic cholesterol. Psyllium, cholestyramine, and the combination increased total bile acid excretion by 26%, 57%, and 79%, respectively. Psyllium affected only unconjugated bile acid excretion while cholestyramine also increased the excretion of conjugated and primary bile acids. Neither agent, nor the combination, affected fecal neutral sterol excretion. We conclude that, while both agents lower cholesterol by a mechanism of increased bile acid excretion, these studies indicate that psyllium does not bind bile acids in vivo and lend further support for the concomitant use of these agents for cholesterol-lowering.