Fungi are among the most primitive organisms that synthesize sterols. The fungal sterol, ergosterol, is similar to animal sterol, cholesterol, but with significant structural differences. The genetics and biochemistry for most of the steps in sterol biosynthesis have been studied in the yeast, Saccharomyces cerevisiae. Yet, little is known of ...

Most animal and human studies show that phytosterols reduce serum/or plasma total cholesterol and low density lipoprotein (LDL) cholesterol levels. Phytosterols are structurally very similar to cholesterol except that they always contain some substitutions at the C24 position on the sterol side chain. Plasma phytosterol levels in mammalian tissue are ...

Terrestrial gastropods contain ecdysteroids, the origins of which are unknown. Whether they are synthesized by the animals or they arise from the diet is an open question. To address this problem, labeled cholesterol and various molecules which are efficiently converted into ecdysone by arthropods were tested as possible ecdysone precursors ...

The Smith-Lemli-Opitz syndrome is an autosomal recessive birth defect (frequency 1:20,000-1:40,000) that results in profound mental retardation, physical deformities, and failure to thrive. It is characterized biochemically by low plasma cholesterol and greatly elevated levels of two dehydrocholesterols, one of which is the cholesterol precursor 7-dehydrocholesterol. To determine whether the ...

Previous studies have demonstrated that changes in the rates of cholesterol biosynthesis can be evaluated by the determination of plasma concentrations of sterol intermediates, including mevalonic acid and lathosterol and that, in normal human subjects, a diurnal rhythm exists in which the highest concentrations of sterol intermediates are observed at ...

Cholesterol absorption and metabolism and LDL and HDL kinetics were investigated in 11 hypercholesterolaemic non-insulin-dependent diabetic men off and on a hypolipidaemic treatment with sitostanol ester, (3 g sitostanol daily) dissolved in rapeseed oil margarine, by a double-blind crossover study design. Serum total, VLDL and LDL cholesterol and apoprotein B ...

Sterol balance studies, using both isotopic and chromatographic techniques, were carried out in hamsters fed semipurified diets to detect changes in sterol metabolism during the early period of the lithogenic stimulus. The balance studies examined animals in the first two weeks on the experimental lithogenic diets. The variables were as ...

1. Serum cholesterol reduction and changes in cholesterol metabolism were studied during rapeseed oil feeding without and with increasing amounts of sitostanol trans-esterified with rapeseed oil fatty acids and dissolved in rapeseed oil mayonnaise. Fifteen mildly hypercholesterolaemic subjects replaced 50 g of their usual dietary fat by 50 g of ...

Serum concentrations and metabolism of cholesterol were studied in vegetarians basally and during a dietary cholesterol load. Cholesterol absorption efficiency was normal and synthesis was slightly enhanced, even though serum cholesterol precursors were not increased. The serum concentrations of total and low-density-lipoprotein cholesterol were decreased proportionally to the reduced intake ...

This study used the rat pancreatoma AR42J cells as model to study hormonal regulation of cholesterol esterase biosynthesis. Our previous studies (Y. Huang and D. Y. Hui, 1991, J. Biol. Chem. 266, 6720-6725) have demonstrated that the AR42J cells responded to cholecystokinin (CCK) and secretin challenge by increasing cholesterol esterase ...

The aim of this study was to assess whether diets enriched in cholesterol, sodium cholate and drugs known to modify liver cholesterol biosynthesis can modulate hepatic lipase (H-TGL) expression and activity in vivo. Female lean Zucker rats, known to be good responders to cholesterol, were fed for 7 days with ...

The effect of rapeseed oil with and without added squalene was studied on serum lipids and cholesterol metabolism. Dietary rapeseed oil reduced LDL cholesterol by 10%, increased cholesterol precursors and plant sterols, and decreased cholestanol in serum during a 6-wk baseline period from initial values. Addition of 1 g squalene ...

Effects of small amounts of sitosterol, sitostanol and sitostanol esters (< 1 g/day of free sterols) dissolved in rapeseed oil (RSO) were studied on serum lipids and cholesterol metabolism in patients with primary hypercholesterolemia and different apolipoprotein E phenotypes on an RSO diet. One of the four groups was an ...

BACKGROUND: The Smith-Lemli-Opitz syndrome (frequency, 1:20,000 to 1:40,000) is defined by a constellation of severe birth defects affecting most organ systems. Abnormalities frequently include profound mental retardation, severe failure to thrive, and a high infant-mortality rate. The syndrome has heretofore been diagnosed only from its clinical presentation. METHODS: Using capillary-column ...

Serum cholesterol values were insufficiently reduced by pravastatin in two different patient populations. Therefore, we studied whether further cholesterol reduction could be achieved by inhibiting both cholesterol synthesis (by pravastatin) and absorption (by neomycin or sitostanol ester). Thus, we measured serum cholesterol, cholesterol precursors (reflecting cholesterol synthesis), cholestanol and plant ...

Compounds that block hepatic cholesterol biosynthesis and secretion may be useful hypocholesterolemic agents. N-[(1,5,9)-trimethyldecyl]-4 alpha,10-dimethyl-8-aza-trans-decal-3 beta-ol (MDL 28,815) has been shown to block cholesterol biosynthesis in 3T3 fibroblasts and it causes cellular accumulation of squalene 2,3-epoxide and squalene 2,3:23,24-diepoxide (squalene epoxides), which suggests that it inhibits 2,3-oxidosqualene cyclase. The purpose ...

Intestinal absorption of cholesterol, campesterol, campestanol, stigmasterol and sitosterol were measured in 10 healthy subjects by an intestinal perfusion technique over a 50 cm segment of the upper jejunum using sitostanol as non-absorbable marker. Cholesterol absorption was highest and averaged 33%., whereas the absorption rate of sitosterol averaged 4.2% and ...

Selective breeding has produced baboon progeny that have low or high response in plasma low-density lipoprotein (LDL) cholesterol when fed a high cholesterol and high fat (HCHF) diet. We examined differences in bile acid metabolism between low and high responding baboons by measuring the most abundant oxysterol in plasma and ...

Sprague-Dawley rats were injected intraperitoneally with [1 alpha, 2 alpha(n)-3H]cholesterol or 25-hydroxy-[26,27-3H]cholesterol, and one and five days later liver and aortic tissues were fixed. The extent to which these sterols were lost from the tissues during preparation for electron microscopy (EM) was examined utilizing different fixation procedures and various protective ...

A randomized double-blind study was made in 67 modestly hypercholesterolemic subjects by replacing 50 g of daily dietary fat by the same amount of a rapeseed oil preparation without and with fat-soluble sitostanol esters. The diet became relatively rich in dietary fat (37%) especially in subjects with a low basal ...

Isoprene is a normal constituent of human breath and may be derived from the cholesterol synthetic pathway. Acute and chronic lovastatin and a cholesterol-supplemented diet were used to determine whether a mechanistic link exists between isoprene and cholesterol biosynthesis in vivo in humans. The acute effects of lovastatin, a competitive ...

Eleven species of Caribbean marine algae (red, green, and brown) were investigated for their cholesterol content. All of them were found to contain this sterol. Consistent with previously reported results, all five red algae contained large quantities of cholesterol. However, the two brown algae and three of the four green ...

Chitosan, a natural product derived from chitin, possesses hypocholesterolemic properties similar to those of cholestyramine, but there has been no report concerning its effects on the equilibrium between dietary cholesterol and de novo cholesterol synthesis in the liver. In this work, we studied the effects of chitosan on plasma and ...

This study was undertaken to compare the ability of two plant sterols to reduce serum levels of lipids and to compare their mechanism of action in nine children with severe familial hypercholesterolemia (total and low-density lipoprotein cholesterol concentrations averaged 9.57 mmol/L (370 mg/dl) and 7.87 mmol/L (301 mg/dl)). After a ...

A new model to study cholesterol uptake in the human intestine in vitro is described. Human small intestine organ cultures were incubated with mixed micelles containing bile acid, phospholipid, and cholesterol or its nonabsorbable analogue, sitosterol; trace amounts of labeled cholesterol or sitosterol were added to the micelles. After incubation, ...

Y-organs of the xanthid crab, Menippe mercenaria, secrete ecdysteroid hormones in vitro, apparently both 3-dehydroecdysone and 25-deoxyecdysone. Studies were initiated on the biosynthetic path(s), in which cholesterol is converted to these ecdysteroids. Crabs were injected with [3H]cholesterol. Y-organs and hemolymph were removed 12 hr later and extracted directly and the ...

Faecal lipid excretion was determined in 16 females on an unrestricted diet and on a fat-restricted diet using a chromatographic method for the simultaneous analysis of faecal lipids. The fat-restricted diet reduced the total quantity of faeces and the amounts of fatty acids, neutral sterols and bile acids excreted were ...

Sixty-two patients aged 19-64 years with primary hypercholesterolemia (mean level of total cholesterol, 10.8 mmol/l) were treated with 80 mg/day lovastatin (L) alone for 18 weeks and, after randomization to either L + 20 g/day guar gum (L + GG) or L + 16 g/day cholestyramine (L + C) treatments, ...

We describe the first Finnish LCAT-deficient family with two affected, one questionably affected and one healthy family member. The affected family members presented stomatocytes in the peripheral blood, exhibited low serum levels of total, LDL and HDL cholesterol, triglycerides, phospholipids and apolipoprotein A-I and especially A-II. Apolipoprotein A-I catabolism was ...

The substrate specificity of cholesterol oxidase from Streptomyces cinnamomeus was examined in oriented sterol monolayers at the air/water interface. Of the cholesterol analogues with structural alterations in the A- or B-ring that were examined, it was observed that 5 alpha-cholestan-3 beta-ol was oxidized almost as fast as cholesterol itself. When ...

Defective lipolysis, steatorrhea, and hypocholesterolemia characterize pancreatic insufficiency. Lipid metabolism in pancreatic insufficiency was studied by measuring serum lipoproteins, cholesterol absorption with double labels and serum plant sterols, and bile acid and cholesterol synthesis with fecal and dietary steroid analysis and cholesterol precursor sterols before and during exogenous pancreatic enzyme ...

Butter was replaced by olive oil in a controlled 100 g fat diet in order to study the effect of saturated fats (SAFA) versus monounsaturated fats (MUFA) on small-bowel sterol excretion in eleven healthy ileostomates. Bile acids and neutral sterols were measured by gas-liquid chromatography. Net cholesterol excretion (excretion minus ...

1. [3-3H]-Squalene was fed to 11 marine sponges containing a mixture of "common" sterol side chains. All of these sponges possess significant quantities of cholesterol, but their ability to biosynthesize it differs widely. 2. All the sponges possess significant quantities of delta 22 sterols, yet none of them was able ...

The hypocholesterolaemic effect of pravastatin 40 mg and lovastatin 40 mg daily has been compared in patients with familial hypercholesterolaemia (FH). Administration of the two drugs was separated by a three-month washout period. The reduction in total serum cholesterol after 1,2 and 4 weeks of treatment was similar after pravastatin ...

We investigated the effects of lovastatin, cholestyramine, and dietary sterol restriction on cholesterol synthesis and low density lipoprotein receptor function in freshly isolated mononuclear leukocytes from two unrelated sitosterolemic families. Total plasma sterol concentrations were elevated in the two homozygous sitosterolemic subjects (343 and 301 vs. 185 mg/dl in controls) ...

Previous comparisons between the Reference and Definitive Methods for measuring serum cholesterol have demonstrated a small but persistent positive bias in the Reference Method, averaging about +1.6%. Here we describe the results of further investigations designed to better characterize the nature of this bias. Analysis of a well-characterized model serum ...

Sitosterolemia and xanthomatosis are characterized by the development of tendon and tuberous xanthomas at an early age and premature atherosclerosis despite normal plasma cholesterol concentrations. The reason(s) for the xanthoma formation and premature atherosclerosis are not clearly understood. The accumulation of sitosterol in the tissues of these patients could be ...

Dietary lipid provides as much as 40% of the caloric intake in the Western diet. Triacylglycerol is the main dietary fat. The human small intestine is also presented daily with 11-12 g of phospholipid, predominantly phosphatidylcholine. The predominant sterol in the Western diet is cholesterol, which is derived from animal ...

A crossover design studying lipid and apoprotein levels in serum and excretion of sterol, nitrogen and fat in ileostomy effluent was performed in 10 subjects fed diets with or without supplementation with brewer's spent grain, which is the residue of barley after the brewing of beer. More cholesterol, nitrogen, fat ...

Brewer's yeast was grown on a defined medium containing tracer 51Cr with or without added chromium. The two batches of yeast contained 10 microgram/g (high-Cr) or 80 ng/g (low-Cr). Extracts were prepared and fractionated. A third batch of yeast (third batch) was grown with added Cr, and fractionated. Rats were ...

Serum albumin, cholinesterase, and cholesterol were measured in ten patients with aplastic anemia and eight with myelodysplastic syndrome who received the administration of recombinant human GM-CSF. Serum albumin, cholinesterase, and cholesterol were significantly lowered by the administration of GM-CSF and recovered after the cessation of GM-CSF. These data suggest that ...

The effects of two different plant sterols on intestinal cholesterol absorption were compared in normal volunteers by an intestinal perfusion study during a control period followed by high dose infusion of sitosterol or sitostanol (3.6 mumol/min), to which subjects were allocated in a randomized manner. Cholesterol absorption during the control ...

Male SEA quail were fed a 0.5% cholesterol supplemented diet, to which was added 0%, 1%, and 2% beta-sitosterol, for a period of seven days. Dietarily administered beta-sitosterol reduced total serum cholesterol levels by 62% and 72% at the 1% and 2% treatment doses, respectively. This hypocholesterolemic activity of sitosterol ...

To study the effects of dietary phytosterols on plasma cholesterol, Wistar rats were fed diets containing a cholesterol overload (24 mg/day), to which phytosterols were added or not (24 or 96 mg/day). The cholesterol overload led to a marked increase in cholesterol, mainly linked to very-low-density and low-density lipoproteins. Phytosterols ...

In this report, an 11-year-old boy with diffuse tendinous and tuberous xanthomatosis and a plasma sterol concentration of 555 mg/dL, consisting primarily of cholesterol, is described. Three months after changing from an unrestricted diet to a cholesterol-lowering diet, his plasma sterol concentration decreased to 221 mg/dL. Because of the degree ...

NB-598, (E)N-ethyl-N-(6,6-dimethyl-2-hepten-4-ynyl)-3-[(3,3'-bith iophen-5-yl)methoxy]benzene-methanamine, was found to inhibit human microsomal squalene epoxidase (from Hep G2 cells) in a competitive manner. NB-598 inhibited cholesterol synthesis from [14C]acetate dose dependently in Hep G2 cells and increased the intracellular radioactivity of squalene. A single oral administration of NB-598 inhibited cholesterol synthesis from [14C]acetate in ...

Squalene, a key intermediate of cholesterol synthesis, is present especially in olive oil. Regulation of cholesterol metabolism by dietary squalene in man is unknown, even though olive oil users in Mediterranean areas have low serum cholesterol levels. We have investigated absorption and serum levels of squalene and cholesterol and cholesterol ...

The hypocholesterolemic drug lovastatin (mevinolin) was found to be very effective in lowering the sterol levels of the wild-type yeast Saccharomyces cerevisiae. Lovastatin dramatically decreased the steryl ester content from 2.62 to 0.8 micrograms/mg (dry weight), whereas the free sterol content decreased only from 2.79 to 2.24 micrograms/mg (dry weight) ...

A common pharmacologic approach to lowering elevated serum cholesterol levels has been to interfere with intestinal sterol absorption. Inhibitors of acyl coenzyme A: cholesterol acyltransferase (ACAT) should produce this effect. In this study, we examined the effects of CL 277,082, N-(2,4-difluorophenyl)-N-(4-neopentylbenzyl)-N-(n-heptyl)urea, an ACAT inhibitor, on cholesterol metabolism in humans. Eight ...

The effects of Simvastatin (MK-733), an inhibitor of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase, on fecal and biliary excretion of sterols and bile acids were examined using rabbits. Multiple doses of MK-733 (10 mg/kg/day) for 7 days were found to increase fecal concentrations of neutral sterols in cholesterol-fed rabbits, but not to ...