Total Amount Of Cholesterol Research Articles

Glibenclamide inhibits cholesterol metabolism in macrophage

Sulfonylureas are generally used in the therapeutic treatment of non-insulin-dependent diabetes mellitus. Little is known, however, whether they also affect the lipid metabolism. Using glibenclamide (GB), a typical sulfonylurea, we have investigated its effects on the lipid metabolism in macrophages, J774 and phorbol ester-treated THP-1 cells. In the whole-cell assay system for cholesteryl ester (CE) accumulation that is induced by addition of chemically modified low-density lipoprotein (LDL), such as Ac-LDL and ox-LDL, GB effectively inhibited the CE accumulation of J774 cells in dose-dependent manners. The inhibition was resulted from increase in free cholesterol but not from change in total cholesterol amount. The results suggest that GB acts on acyl-CoA: cholesterol acyltransferase (ACAT) and inhibits its activity. To confirm the possibility, we then tested GB by another assay system using ACAT that was solubilized from the cells and reconstituted into the liposome composed of phosphatidyl choline- cholesterol. GB inhibition was not so much effective as those by CI-976 and NTE-122, known ACAT inhibitors, but the inhibition was complete in the presence of 100 microM GB. Using cell homogenates of PMA-stimulated THP-1 cells, GB also inhibited the ACAT activity to the level of undifferentiated THP-1 cells. These results indicate that GB acts as ACAT inhibitor but the chemical structure is quite different from the conventional ACAT inhibitors, suggesting it can be a seed to generate potential ACAT inhibitors which do not exhibit toxicity in adrenal gland.

Homocysteine stimulates the production and secretion of cholesterol in hepatic cells

Homocysteinemia and hypercholesterolemia are important risk factors associated with the occurrence of arteriosclerotic vascular diseases. A positive correlation between plasma levels of homocysteine and cholesterol was found in homocysteinemic patients as well as in experimental animals. In the present study, the effect of homocysteine on the production and secretion of cholesterol in human hepatoma cell line HepG2 cells was investigated. When cells were incubated with 4 mM homocysteine, the amounts of total cholesterol produced as well as the cholesterol secreted by these cells were significantly increased (from 32±5 to 74±5 nmol/mg cellular protein). Further biochemical analyses revealed that the increase in cholesterol was resulted from an enhancement in the production and secretion of the unesterified cholesterol with no concomitant change in the level of cholesteryl esters. The activity of intracellular 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase was markedly elevated by 131% and 190% after cells were incubated with homocysteine for 24 and 48 h. Homocysteine also stimulated the secretion of apo B100 by HepG2 cells (from 0.84±0.11 to 1.37±0.12 μg apolipoprotein B/mg cellular protein). Our results demonstrate that homocysteine stimulates the production and secretion of cholesterol and apolipoprotein B100 in HepG2 cells. The increase in the production of cholesterol induced by homocysteine may contribute to the pathogenesis of arteriosclerosis.

Increased Plasma, Biliary, and Hepatic Cholesterol Precursors in Pigs with Ileal Autotransplantation-Induced Malabsorption of Cholesterol and Bile Acids

Background: Small-bowel transplantation impairs intestinal absorptive function for unknown reasons. Methods: The proportions of plasma, biliary, and hepatic cholesterol precursors to cholesterol were determined by gas-liquid chromatography after resection of the proximal 75% of the porcine jejunoileum (n = 15) and autotransplantation of the remaining ileum (n = 15) and were related to in vivo absorption and fecal excretion of cholesterol. Results: Ileal autotransplantation significantly decreased serum (18%; P < 0.05) and liver (7.6%; P < 0.05) cholesterol content, the esterification percentage of serum cholesterol (5.1%; P < 0.0001), and the total amount of cholesterol absorbed (48%; P < 0.05) and increased fecal excretion of bile acids (108%; P < 0.0001), net cholesterol elimination (53%; P < 0.001), and the proportions of plasma (207%; P < 0.0001), biliary (183%; P < 0.0001), and hepatic (114%; P < 0.0001) cholesterol precursors. The increases were most striking for the side-chain-saturated demethylated sterols, cholestenol and lathosterol, and monomethyl sterols, whose bile/liver and plasma/liver ratios were increased in the autotransplantation group. Plasma, biliary, and hepatic precursor proportions were positively related to each other and similarly correlated with fecal bile acids and the net elimination of cholesterol in feces. Conclusions: These findings suggest that ileal autotransplantation in pigs with proximal gut resection increased the levels of cholesterol precursor sterols in plasma, bile, and liver mainly due to a bile-acid-malabsorption-induced increase in hepatic synthesis of cholesterol. Enhanced secretion of cholesterol precursors from the liver into the plasma and bile may have contributed to their increased values during the increased rate of cholesterogenesis.

Blood lipoproteins and their effect on contractile function of vessels in rats of different age

Experiments on adult and old rats have shown that blood lipoproteins (LP) exert a dilatatory effect on isolated segments of the thoracic aorta in animals of different age. In old versus adult animals, the sensitivity of vessels in all LP fractions (LDL, VLDL and HDL (low, very low and high density LP)) was lower as a result of age changes in the reactivity of vessels. The capacity of HDL to produce a vasodilatatory effect decreases with age, which may be linked to changes in the lipid and apolipoprotein composition. The results revealed a decrease in the level of phospholipids and an increase in the amount of total cholesterol in HDL observed in old age. The capacities of LDL and VLDL to exert a vascular dilatatory action remained unchanged with age.

Quantitation of the Pool of Cholesterol Associated with Acyl-CoA:Cholesterol Acyltransferase in Human Fibroblasts

The esterification of cholesterol in homogenates of human fibroblasts was explored as a means of estimating the size of the pool of cholesterol associated with the endoplasmic reticulum (ER) in vivo. The rationale was that the acyl-coenzyme A:cholesterol acyltransferase (ACAT) in homogenates should have access only to cholesterol associated with the (rough) ER membrane fragments in which it resides. Reacting whole homogenates to completion with an excess of [14C]oleoyl-CoA converted approximately 0.1-2% of total cell-free cholesterol to [14C]cholesteryl esters. Control studies indicated that membranes not associated with ACAT did not contribute cholesterol to this reaction. The extent of in vitro cholesterol esterification varied with pretreatment of the cells. Exposing intact cells to serum lipoproteins, oxysterols, or sphingomyelinase increased cholesterol esterification in homogenates severalfold; exposing the cells to mevinolin or cholesterol oxidase had the opposite effect. The variation in cholesterol esterification did not correlate with either the total cellular cholesterol or the intrinsic activity of ACAT, neither of which was changed significantly by the pretreatments. Rather, the total amount of cholesterol esterified in homogenates paralleled the rate of cholesterol esterification in the corresponding intact cells. The pool of cholesterol esterified in vitro therefore appears to reflect that associated with the ER in vivo. Since several of the mechanisms keeping cell cholesterol under tight feedback control are themselves located in the ER, this pool might not only be regulated physiologically, but could, in turn, help to regulate homeostatic effector pathways.

Sources of cholesterol during development of the rat fetus and fetal organs

Female rats at various stages of pregnancy were injected intraperitoneally with [3H]water; 4 h later, they were killed, the uterus was removed, and the fetuses were dissected. Lipids were isolated and fractionated by HPLC and the total amount of cholesterol in each organ, as well as radioactivity incorporated into cholesterol and cholesterol precursors, were determined. From the data for cholesterol content at each age we calculated the rate of accumulation of cholesterol during fetal development. As incorporation of label from [3H]water takes place with a stoichiometry defined by a known biosynthetic pathway, we were also able to determine the fraction of cholesterol accumulating in each organ that had been newly synthesized. For the fetus as a whole, more than 93% of the cholesterol accumulating during development was newly synthesized. As the specific radioactivity of cholesterol in the maternal circulation was negligible (because synthesis of cholesterol by maternal liver was suppressed by inclusion of cholesterol in the diet), we conclude that the fetus synthesizes nearly all of its own cholesterol; neither the maternal circulation nor the placenta/yolk sac contribute significant amounts of cholesterol to the fetus. We were also able to quantitate trafficking of cholesterol between fetal organs. Fetal brain is responsible for the synthesis of all of its own cholesterol. In contrast, fetal liver exports cholesterol into the fetal circulation and supplies about half of the cholesterol for development of heart, lung, and kidney.

Protective role of intraperitoneally administrated vitamin E and selenium on the levels of total lipid, total cholesterol, and fatty acid composition of muscle and liver tissues in rats.

The aim of this work was to determine the protective effects of intraperitoneally administrated vitamin E and Se on total lipid, total cholesterol, and fatty acid composition of rat liver and muscle tissues. Total lipid content of muscle tissue in Se and combination groups decreased as compared to the control group. However, the level of total lipid in the liver tissues was seen to decrease only in the combination group (P < 0.05). While the amount of total cholesterol in liver tissue was lower (P < 0.05) in the vitamin E and combination groups, the amount of total cholesterol in muscle tissue decreased (P < 0.05) in the combination group. The amount of linoleic acid in muscle tissue slightly decreased (P < 0.05), whereas the eicosenoic and eicosatrienoic acid amounts significantly increased (P < 0.01, P < 0.001) in the vitamin E group as compared to the control group. The amounts of most fatty acid decreased (P < 0.05) in the combination group. The proportions of eicosenoic, eicosatrienoic, and total polyunsaturated fatty acid (PUFA) within the total fatty acid were higher (P < 0.05) in vitamin E group, whereas these fatty acids proportions were lower (P < 0.05) in the Se group. Although the proportions of palmitic, linolenic, and total saturated fatty acids were low (P < 0.05), oleic and total unsaturated fatty acid proportions were higher (P < 0.05) in the combination group than in the control group. The amount of palmitic acid and total saturated fatty acid in liver tissue decreased (P < 0.01 and P < 0.05, respectively) in the vitamin E and combination groups. However, the amount of linoleic acid only decreased (P < 0.05) in the combination group. The amount of PUFA was slightly higher (P < 0.05) in vitamin E. The proportions of stearic acid and linoleic acid decreased (P < 0.05) both in the Se and combination groups. However, the proportions of eicosatrienoic, omega 6, and PUFA were slightly higher (P < 0.05) in the vitamin E group, but total saturated fatty acid proportion significantly decreased (P < 0.01) in both the vitamin E and combination groups. In conclusion, the level of total lipid and cholesterol in muscle and liver tissues were reduced by administrating vitamin E and Se together. Additionally, the fatty acid synthesis in the muscle and liver tissues was decreased by this process. However, it was observed that the protective effect of intraperitoneally administrated vitamin E was higher than Se on fatty acid composition in muscle and liver tissues.

Anti-hyperliposis effect of maitake fruit body (Grifola frondosa). I.

Experimental rat models (5-week-old Sprague-Dawley rats) with hyperlipemia were prepared by feeding high-cholesterol feed containing sodium cholate and casein as a protein source. Dried maitake (Grifola frondosa) powder was mixed with the basic high-cholesterol feed and the serum lipids were periodically measured. Values of cholesterol, triglyceride and phospholipid in serum of rats in the maitake-feed group were suppressed by 0.3-0.8 times those in animals fed the basic feed, the latter values being close to those in rats given normal feed. The value of high density lipoprotein (HDL)-cholesterol in serum which is generally reduced by the ingestion of high-cholesterol feed remained the level it was at the beginning of the experiment. Weights of extirpated liver and epididymal fat-pads were significantly less (0.6-0.7 times) than those in the basic feed group, indicating that maitake inhibits lipid accumulation in the body. Liver lipids were also measured and the values were found to be decreased by maitake administration as true of serum lipid, suggesting maitake has an anti-liver lipid activity. Measurement of the amount of total cholesterol and bile acid in feces showed, the ratio of cholesterol-excretion had increased 1.8 times and bile acid-excretion 3 fold by maitake treatment. From these results, it is believed that maitake helps to improve the lipid metabolism as it inhibits both liver lipid and serum lipid which are increased by the ingestion of high-fat feed.

Changes in the Nutrient Content of School Lunches: Results from the CATCH Eat Smart Food Service Intervention

Background.The Child and Adolescent Trial for Cardiovascular Health (CATCH) tested the effectiveness of a multilevel intervention aimed at promoting a healthful school environment and positive eating and physical activity behaviors in children. The CATCH Eat Smart Program targeted the school food service staff and aimed to lower the total fat, saturated fat, and sodium content of school meals.Methods.The Eat Smart intervention was conducted in 56 intervention schools over a 212-year period. Five consecutive days of school menu, recipe, and vendor product information were collected from intervention and control schools at three intervals, Fall 1991, Spring 1993, and Spring 1994, to assess the nutrient content of school menus as offered.Results.There was a significantly greater mean reduction in the percentage of calories from total fat (adjusted mean difference −4.1%;P< 0.0001) and saturated fat (adjusted mean difference −1.3%;P= 0.003) in intervention compared with control schools from baseline to follow-up. Although the sodium content of school lunches increased in both conditions, the mean increase was significantly lower in intervention schools (adjusted mean difference −89 mg;P= 0.034). There were no statistically significant differences for total amounts of cholesterol, carbohydrate, protein, dietary fiber, total sugars, calcium, iron, vitamin A value, and vitamin C. Average total calories decreased significantly; however, the mean total calories (683 kcal) for intervention schools remained above one-third of the Recommended Dietary Allowances for this age group.Conclusions.The CATCH Eat Smart intervention successfully lowered the total fat and saturated fat content of school lunches as offered, while maintaining recommended amounts of calories and essential nutrients.

LIPID CONTENT AND FATTY ACID PROFILES OF SOME LESSER KNOWN NIGERIAN FOODS

The lipid content and fatty acid profiles of seven lesser known protein foods in Nigeria, which include raffia palm and oil palm weevils (Rhynchophorus sp.), shrimps (Palaemonetes sp.), periwinkles (Pachynelania byronesis), snails (Vicapara quadrata), tropical oysters (Thais haemastrama) and crayfish (Palaemonetes varians), were determined. The total lipid content (% fresh weight, FW) ranged between 1.8 ± 0.1 and 9.8 ± 0.1. The range of values for neutral lipids, total phospholipids, and glycolipids (mg/g FW) was 10.1 ± 0.7 to 53.6 ± 1.5, 6.1 ± 1.3 to 30.1 ± 1.5, and 2.5 ± 0.2 to 13.1 ± 0.9, while those of total cholesterol and triacylglycerol content (mg/g neutral lipids) were 1.4 ± 0.1 to 7.1 ± 0.2 and 8.3 ± 1.1 to 47.0 ± 1.5, respectively. Crayfish and palm weevils contained higher amounts of total cholesterol and phospholipids, compared with the rest of the foods. The fatty acid profiles showed variation among the different foods. Palm weevils, periwinkles, snails and tropical oysters were shown to contain substantial amounts of essential fatty acids, especially linolenic acid (C18:3n3).

Abnormal lipid composition of bronchoalveolar lavage fluid obtained from individuals with AIDS-related lung disease.

Surfactant lipids are not only important to the physiologic function of the lungs, but may also influence disease processes like Pneumocystis pneumonia, in which the interaction of host-defense cells with pathogen occurs within the confines of the surfactant-rich alveolar hypophase. In the present studies the lipid profile of bronchoalveolar lavage fluid (BALF) was characterized in subjects with AIDS-related lung diseases including Pneumocystis pneumonia. BALF lipid and total protein measurements were made in 43 subjects with acquired immune deficiency syndrome (AIDS)-related lung disease and compared with those made in 50 normal human immunodeficiency virus (HIV)-seronegative controls. The AIDS patient samples contained significantly greater amounts of total cholesterol, phosphatidylglycerol (PG), and protein than the control samples; in contrast to previous observations in rodent P. carinii infection, no differences were seen in total phospholipid (PL) or phosphatidylcholine (PC) in the two groups. The proportions of several of these lipids were deranged in BALF obtained from the patient group: PG/PL and PC/cholesterol differed significantly from normal samples. In the subset of patients with AIDS-related Pneumocystis pneumonia, no correlation was apparent between discrete BALF lipids and clinical indices reflective of disease severity. Using these measurements to approximate the lipid composition of the alveolar microenvironment in AIDS-related lung disease, we performed experiments in which normal human alveolar macrophages were exposed to exogenous liposomal lipids and then challenged with P. carinii. The ingestion but not binding of P. carinii by macrophages was diminished as a result of lipid exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholesterol content of lean and fat from beef, pork, and lamb cuts

Fifteen carcasses—five each of beef, pork, and lamb—were selected. Longissimus and semi-membranosus muscles were removed from each side; three cuts were removed from each muscle. The steaks and chops were divided into one of three external fat treatments: (1) 0 cm external fat remaining, (2) 0.6 cm (combined lean and fat) fat remaining, and (3) 0.6 cm (separable lean and separable fat) fat remaining. Cholesterol and total lipid were analyzed for both raw and cooked samples in each external fat treatment. With the exception of longissimus lamb chops, cooking steaks or chops with or without external fat did not affect the total amount of cholesterol in the separable lean. The longissimus lamb chops, cooked with external fat, had a higher ( P < 0.05) amount of cholesterol in the separable lean than chops cooked without external fat. There was no significant migration of cholesterol from the adipose tissue into the lean tissue in the beef and pork species, but there was migration in lamb. Cholesterol migration in lamb possibly was due to the relationship between the proportion of fat and lean in the smaller lamb chops.

Short- and long-term effects of biliary drainage on hepatic cholesterol metabolism in the rat

The present study concerns short- and long-term effects of interruption of the enterohepatic circulation (EHC) on hepatic cholesterol metabolism and biliary secretion in rats. For this purpose, we employed a technique that allows reversible interruption of the EHC, during normal feeding conditions, and excludes effects of anaesthesia and surgical trauma. [3H]Cholesteryl oleate-labelled human low-density lipoprotein (LDL) was injected intravenously in rats with (1) chronically (8 days) interrupted EHC, (2) interrupted EHC at the time of LDL injection and (3) intact EHC. During the first 3 h after interruption of the EHC, bile flow decreased to 50% and biliary bile acid, phospholipid and cholesterol secretion to 5%, 11% and 19% of their initial values respectively. After 8 days of bile diversion, biliary cholesterol output and bile flow were at that same level, but bile acid output was increased 2-3-fold and phospholipid output was about 2 times lower. The total amount of cholesterol in the liver decreased after interruption of the EHC, which was mainly due to a decrease in the amount of cholesteryl ester. Plasma disappearance of LDL was not affected by interruption of the EHC. Biliary secretion of LDL-derived radioactivity occurred 2-4 times faster in chronically interrupted rats as compared with the excretion immediately after interruption of the EHC. Radioactivity was mainly in the form of bile acids under both conditions. This study demonstrates the very rapid changes that occur in cholesterol metabolism and biliary lipid composition after interruption of the EHC. These changes must be taken into account in studies concerning hepatic metabolism of lipoprotein cholesterol and subsequent secretion into bile.

Abnormalities of composition and of in vitro lipolysis products of human small very low density lipoproteins in hypertriglyceridemia

Small (S f 20–100) very low density lipoprotein (VLDL) particles were prepared by density gradient ultracentrifugation of plasma from normolipidemic and type IV hypertriglyceridemic post-infarction patients and healthy controls. The small VLDL separated from the plasma of severely hypertriglyceridemic post-infarction patients were found to contain twice the amount of cholesteryl esters per particle, compared with small VLDL from normolipidemic patients and healthy controls. There was a linear increase in the percentage of cholesterol that was esterified in the small VLDL with the serum VLDL triglyceride concentration (r = 0.66). When incubated for two hours with bovine lipoprotein lipase in excess and bovine albumin as a free fatty acid acceptor at one and the same triglyceride concentration in the medium, the end-product isolated by ultracentrifugation varied as a function of the serum VLDL triglyceride level. The amount of glyceride-glycerol recovered after two hours of incubation with lipoprotein lipase was 13.3 ± 1.3% (mean ± SEM) of the initial values and did not correlate with the VLDL triglyceride level. With rising serum VLDL triglyceride concentration, the product isolated in the low density lipoprotein (LDL) density region (1.006 < d < 1.063 kg/1) contained more total cholesterol and phospholipids. The linear correlation coefficients for these relations were 0.65 and 0.58 for cholesterol and phospholipids respectively. The ratio of total cholesterol to insoluble protein in the LDL density range after lipolysis rose with increasing serum VLDL triglyceride level ( r = 0.68). The end-product was further characterized by density gradient ultracentrifugation of the incubate. In vitro LDL derived by lipolysis of normolipidemic small VLDL was denser than in vitro LDL of hypertriglyceridemic small VLDL. A significant relation was found between the percentage of cholesteryl esters of total cholesterol in the substrate and the relative amount of total cholesterol recovered in the LDL density fraction after lipolysis ( r = 0.69). We suggest that the enrichment with cholesteryl esters of small VLDL from type IV hypertriglyceridemic patients is caused by lipid transfer from LDL and high density lipoprotein (HDL) and that the change in VLDL particle composition influences the precursor-product relationship to LDL.

Age-associated changes in dolichol and dolichyl phosphate metabolism in the kidneys and liver of mice

The total amounts of cholesterol, dolichol and dolichyl phosphate (Dol-P) in kidneys and liver from 1- and 24-month-old mice were measured after saponification of the tissues. The cholesterol content of kidneys decreased by about 4-fold per g of tissue between the two ages, while the amount of cholesterol/g liver remained constant. The dolichol content of both tissues increased by about 2-fold. The amount of Dol-P in kidneys increased by 7-fold over 23 months, while the concentration in liver decreased some 6-fold. Metabolic labelling experiments using tritiated water demonstrated that the rate of synthesis of total dolichol (dolichol + Dol-P) in the kidneys did not change as a function of age. However, the kidneys of young mice incorporated 3-fold more radioactivity into dolichol than Dol-P, whereas this distribution was reversed in old mice. In liver, the rate of dolichol synthesis decreased 2-fold over 23 months. It was not possible to compare the rates of Dol-P biosynthesis between ages as Dol-P was undetectable in liver of old mice. The relative abundance of the 19 isoprene unit homologs of both dolichol and Dol-P decreased approx. 5% while the 17 isoprene unit homologs increased by a similar amount in both tissues of the old mice.

Solubilization of lipids from hamster bile-canalicular and contiguous membranes and from human erythrocyte membranes by conjugated bile salts.

We have demonstrated in vitro the efficacy of the taurine-conjugated dihydroxy bile salts deoxycholate and chenodeoxycholate in solubilizing both cholesterol and phospholipid from hamster liver bile-canalicular and contiguous membranes and from human erythrocyte membrane. On the other hand, the dihydroxy bile salt ursodeoxycholate and the trihydroxy bile salt cholate solubilize much less lipid. The lipid solubilization by the four bile salts correlated well with their hydrophobicity: glycochenodeoxycolate, which is more hydrophobic than the tauro derivative, also solubilized more lipid. All the dihydroxy bile salts have a threshold concentration above which lipid solubilization increases rapidly; this correlates approximately with the critical micellar concentration. The non-micelle-forming bile salt dehydrocholate solubilized no lipid at all up to 32 mM. All the dihydroxy bile acids are much more efficient at solubilizing phospholipid than cholesterol. Cholate does not show such a pronounced discrimination. Lipid solubilization by chenodeoxycholate was essentially complete within 1 min, whereas that by cholate was linear up to 5 min. Maximal lipid solubilization with chenodeoxycholate occurred at 8-12 mM; solubilization by cholate was linear up to 32 mM. Ursodeoxycholate was the only dihydroxy bile salt which was able to solubilize phospholipid (although not cholesterol) below the critical micellar concentration. This similarity between cholate and ursodeoxycholate may reflect their ability to form a more extensive liquid-crystal system. Membrane specificity was demonstrated only inasmuch as the lower the cholesterol/phospholipid ratio in the membrane, the greater the fractional solubilization of cholesterol by bile salts, i.e. the total amount of cholesterol solubilized depended only on the bile-salt concentration. On the other hand, the total amount of phospholipid solubilized decreased with increasing cholesterol/phospholipid ratio in the membrane.

臍帯血リポ蛋白およびアポ蛋白の性質について

Cord serum lipoproteins were characterized in terms of lipid and apoprotein compositions in comparison with adult lipoproteins.Cord sera were obtained from normal babies of normal mothers and sera were also taken from the same babies one and five days after the births. Adult sera were obtained from normal subjects. Lipoproteins were separated by sequential ultracentrifugation by adjusting density with KBr, and in some experiments a density gradient centrifugation was used to obtain each lipoprotein. Apoprotein (apo) A-I, A-II, B, C-II, C-III, and E were determined by single radial immunodiffusion method. Apo B subclasses were analyzed by polyacrylamide gel electrophoresis in the presence of SDS. HDL subclasses were separated by gradient gel electrophoresis using Pharmacia PAA 4/30 gels. Cord serum total cholesterol (TC), triacylglycerol (TG) and phospholipid (PL) levels were significantly lower than those of adult serum; one-third, one-fourth, and a half of that of adult serum respectively. Baby serum lipid levels increased rapidly with time in as few as five days. Lipid contents of each lipoprotein in cord serum were significantly lower than those of adult lipoproteins, but HDL lipids were in a lower range of normal adult HDL lipids, while cord serum VLDL and LDL lipids were extremely lower. The same amount of TC was found in HDL and LDL in cord serum, which shows that cord serum is relative hyperalpha-lipoproteinema. Cord serum VLDL contains less TG/protein compared with adult VLDL, while the TC/protein ratio was comparable to that of adult VLDL. In cord LDL TC/protein was similar to that in adult LDL, but the PL/protein was twice as high as that of adult LDL. Apoprotein composition of each lipoprotein in cord serum was very similar to that in adult serum. However, cord serum HDL contained more apo E than adult HDL. Cord serum HDL was rich in smaller-sized subclasses compared with adult HDL. SDS-PAGE disclosed that the molecular weight of apo B of both adult and cord sera was mainly composed of a 290k to 300k dalton particle corresponding to apo B-48. In adult apo B a band of 120k dalton, which was thought of as apo B-48, was recognized. In cord serum apo B, there was a trace amount of B-48.Cord serum was poor in VLDL and rich in HDL, and the amount of TC in HDL and in HDL was the same. Cord serum HDL contained more apo E than adult HDL. These data may imply that HDL can play a role in cholesterol supply to peripheral cells by virtue of apo E in fetus, because apo E is able to bind apo B, E receptor in peripheral cells. The fact that fetus serum contains apo B-48 shows that apo B-48 could be also synthesized in fetal liver or secreted from the intestine without food ingestion. Lipoprotein metabolism in fetus should be further investigated in a system including cells.

Comparison of the Cholesteryl Ester Composition of Human Milk from Preterm and Term Mothers

SummaryMilk was obtained on postpartum days 2–3 (colostrum) and days 7, 21, 42, and 84 from mothers of 18 very premature (VPT, 26–30 weeks gestational age), 28 premature (PT, 31–36 weeks), and 6 term (T, 37–40 weeks) infants. Lipids were extracted in chloroform‐methanol and analyzed by thin‐layer (TLC) and gas liquid chromatography (GLC). Fatty acid composition of cholesteryl esters was determined by GLC after isolation of cholesteryl esters by preparative TLC and preparation of methyl esters of the constituent fatty acids. As lactation progressed, amounts of total cholesterol and cholesteryl esters declined. Cholesteryl esters decreased from about 5 mg/dl in colostrum to 1 mg/dl in mature milk. The cholesteryl esters of colostrum from mothers of premature infants were different in fatty acid composition from those of term infants. Proportions of medium‐chain saturated fatty acids (12:0, 14:0, 16:0) of preterm colostrum (VPT and PT) were considerably lower than in term colostrum: 23% of total fatty acids versus 35%. Proportions of 18:3, 20:3, and 20:4 of VPT (5.6%) and PT (6.2%) colostrum were considerably higher than T colostrum (1.8%). The fatty acid composition of cholesteryl esters of VPT, PT, and T milk was relatively similar at all subsequent lactation periods. Fatty acids esterified with cholesterol in weight percents were as follows: 10:0, 0.7; 12:0, 2.6; 14:0, 2.3; 16:0, 11.4; 16:1, 5.0; 18:0, 8.8; 18:1, 32.9; 18:2, 30.6; 18:3, 1.7; 20:3, 0.9; and 20:4, 1.8. Unsaturated fatty acids contributed 73 wt % of fatty acids in cholesteryl esters, which is considerably higher than in milk triglycerides. The greatest difference occurred in 18:2 content, which was 30.6% in cholesteryl esters and only 13.0% of total fatty acids in milk. Results suggest that unsaturated fatty acids are associated preferentially with the cholesteryl ester fraction and that the fatty acid composition of cholesteryl esters differs from the composition of total milk lipid.

The effect of colchicine on the development of lithocholic acid-induced cholestasis. A study of the role of microtubules in intracellular cholesterol transport.

The pathogenesis of lithocholic acid (LCA-Na)-induced cholestasis involves a rapid accumulation of cholesterol in the bile canalicular membrane. Since microtubules play an important role in the intracellular transport of many materials, including cholesterol, the present study was undertaken to assess the extent to which they participate in the development of LCA-Na-induced cholestasis. Rats were pretreated with either colchicine (0.2 mumol/100 g body wt.) or saline solution 90 min before injection with LCA-Na (12 mumol/100 g body wt.). Colchicine, although not increasing bile flow by itself, significantly reduced the cholestasis caused by LCA-Na (57-32% reduction in bile flow) without affecting its metabolism into less toxic bile acids or its distribution in blood, liver or bile. Bile canalicular membranes isolated from animals treated with a combination of colchicine and LCA-Na contained less cholesterol than those treated with LCA-Na alone. However, membranes obtained from rats treated with colchicine alone contained much less cholesterol than did controls. It was found that the total amount of cholesterol accumulated within the bile canalicular membrane following LCA-Na treatment (LCA-Na + colchicine versus colchicine alone compared with LCA-Na versus controls) was unchanged by colchicine treatment. In view of these findings it is suggested that the total amount of cholesterol present within the bile canalicular membrane determines the extent of LCA-Na-induced cholestasis, LCA-Na probably moves cholesterol to the bile canalicular membrane via a microtubule independent pathway, and microtubules are unlikely to function in the transcellular transport of LCA-Na.

実験的動脈硬化における動脈脂質沈着とエラスチンの代謝について

Experimental atherosclerosis was induced in rats by administering Vit. D2 and atherogenic diet in order to examine the relation between metabolism of aortic elastin and lipid deposition.It was found as the result that 1) Relative amount of total cholesterol (free and ester) and C18:1/C18:2 in elastin fr. of the aorta was tend to increase. On the other hand, relative amounts of triglyceride and phospholipid in the elastin fr, were tend to decrease more in the induced atherosclerotic aorta than in the control one. 2) Residual radioactivity (3H) in urine, serum and aortic elastin fr, in the induced atherosclerotic rats after administering 27.8μCi/rat/day of 3H-Lys for 10 days, was examined, and it was found that the radioactivity was tend to be higher in the atherosclerotic rats than in the control one, which might reflect the fact that the turnover of elastin was decreased more in the atherosclerotic rats. 3) Urinary desmosine, as determined by radioimmunoassay in atherosclerotic rats was tend to be lower than in the control rats at various stages (in 2, 4, 6, 8, 10 weeks). It may be indicated that the turnover of elastin was slower in the atherosclerotic rats than in the normal ones. 4) Externally administered porcine pancreatic elastase preparation might exert such improving effects as stated above (especially the activation of elastin turnover, presumably resulting from the accelated degradation of elastin). The present data suggested that abnormal metabolism of elastin could be one of the factors of lipid deposition in atherosclerosis.