| For medical practitioners and the general public - Cholesterol Journal Article Catalog. |
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| Blood-lipid and lactation-stage factors affecting serum vitamin E concentrations and vitamin E cholesterol ratios in dairy cattle Herdt, T. H. and J. C. Smith (1996), J Vet Diagn Invest 8(2): 228-32. Abstract: The distribution of cholesterol and vitamin E among the various lipoprotein density fractions in bovine blood was measured. The percentage of total plasma vitamin E and cholesterol in the various lipoprotein fractions was very-low-density lipoprotein, 2% and 2%, respectively; low-density lipoprotein, 17% and 22%, respectively, and high-density lipoprotein. 77% and 72%, respectively. Only 3% of plasma vitamin E was not associated with the lipoproteins. Vitamin E cholesterol ratios were not significantly different among lipoprotein fractions (P = 0.3). These results indicate that vitamin E and cholesterol are distributed in equal proportions among lipoprotein fractions. Moreover, the results suggest that variation in the proportions of lipoproteins in the different density fractions would not affect the overall vitamin E cholesterol ratio of plasma. The results further imply that the total plasma vitamin E cholesterol ratio is a valid relative estimator of the vitamin E concentration per lipoprotein particle, regardless of the density distribution of particles. Total serum vitamin E and cholesterol concentrations and their ratio were then determined in commercial diary cattle in various phases of the lactation cycle. There was a significant lactation-stage effect on the serum concentration of each analyte, as well as on their ratio. However, the magnitude of the effect was much less for the ratio than for either vitamin E or cholesterol alone. These results imply that lactation stage affects serum vitamin E concentrations by influencing both the concentration of lipoprotein particles and the concentration of vitamin E within individual particles. |
| Blue ear drum and cholesterol granuloma DeGuine, C. and J. L. Pulec (2000), Ear Nose Throat J 79(8): 542. |
| Blunted feedback suppression of SREBP processing by dietary cholesterol in transgenic mice expressing sterol-resistant SCAP(D443N) Korn, B. S., I. Shimomura, et al. (1998), J Clin Invest 102(12): 2050-60. Abstract: Feedback regulation of cholesterol biosynthesis is mediated by membrane-bound transcription factors designated sterol regulatory element-binding proteins (SREBP)-1 and -2. In sterol-deprived cultured cells, SREBPs are released from membranes by a proteolytic process that is stimulated by SREBP cleavage-activating protein (SCAP), a membrane protein containing a sterol-sensing domain. Sterols suppress SREBP cleavage by blocking the action of SCAP, thereby decreasing cholesterol synthesis. A point mutation in SCAP(D443N) causes resistance to sterol suppression. In this article, we produced transgenic mice that express mutant SCAP(D443N) in liver. In these livers the nuclear content of SREBP-1 and -2 was increased, mRNAs encoding proteins involved in uptake and synthesis of cholesterol and fatty acids were elevated, and the livers were engorged with cholesteryl esters and triglycerides enriched in monounsaturated fatty acids. When the mice were challenged with a high cholesterol diet, cleavage of SREBP-1 and -2 was reduced in wild-type livers and less so in transgenic livers. We conclude that SCAP(D443N) stimulates proteolytic processing of native SREBPs in liver and decreases the normal sterol-mediated feedback regulation of SREBP cleavage, suggesting a central role for SCAP as a sterol sensor in liver. |
| Body fat and fat distribution by anthropometry and the response to high-fat cholesterol-containing diet in monkeys Gray, D. S., R. C. Sharma, et al. (1993), Exp Mol Pathol 58(1): 53-60. Abstract: Considerable variability exists among individuals in the response of plasma cholesterol to changes in dietary fat and cholesterol, and obesity is one variable reported to affect this response. This study was performed to determine the relationship between body fat and changes in plasma cholesterol in cynomolgus monkeys fed a high-fat cholesterol-containing diet for 12 months. The animals gained significant body weight (body mass index increased from 30.5 +/- 0.5 to 35.7 +/- 2.8 kg/m2) and skinfold parameters of body fat increased as well. Total cholesterol increased from 109 +/- 4 to 390 +/- 25 mg/dl (P < 0.001), and there were also significant increases in LDL- and HDL-cholesterol and triglyceride. While there was very little relationship between body fat and plasma lipids before the diet, after 12 months, there were significant negative correlations between total and LDL-cholesterol and anthropometric measures of body fat (r ranged from -0.37 to -0.55, P < 0.01). The correlations were not affected when the effects of baseline body mass index and serum cholesterol and total food intake were controlled by partial correlation analysis. In this sample of animals, the acquisition of greater body fat appeared to protect against rises in cholesterol in response to consumption of a high-fat cholesterol-containing diet. |
| Body fat distribution affects responses to high fat cholesterol containing diet in male cynomolgus monkeys Gray, D. S., R. C. Sharma, et al. (1991), Atherosclerosis 88(1): 93-5. |
| Body fat distribution is a determinant of the high-density lipoprotein response to dietary fat and cholesterol in women Clifton, P. M., M. Abbey, et al. (1995), Arterioscler Thromb Vasc Biol 15(8): 1070-8. Abstract: We have conducted a dietary trial that addressed the factors influencing the variability in plasma lipids in response to dietary fat and cholesterol with a focus on the effects of gender and body fat distribution. Sixty-seven women and 53 men were selected so that overall men and women had a similar mean age, LDL cholesterol, and body mass index. After a 2-week low-fat period subjects were given two liquid supplements for 3 weeks each, one that contained 31 to 40 g fat and 650 to 845 mg cholesterol, and one that was fat free. Measurements included plasma lipids and lipoproteins, glucose, insulin, hepatic triglyceride lipase activity, apolipoprotein E polymorphism, and three indexes of body fat (body mass index, waist girth, and waist-hip ratio). In response to dietary fat and cholesterol supplementation only the changes in HDL cholesterol, especially in HDL2, differed between the sexes. Although on univariate analysis lipoprotein changes were predicted by baseline lipoprotein levels, body mass index, waist girth, waist-hip ratio, hepatic triglyceride lipase activity, and insulin, multiple regression showed only waist-hip ratio to predict changes in HDL2 cholesterol in women and body mass index and baseline HDL2 cholesterol in men. Changes in LDL were predicted by baseline LDL cholesterol in women and apolipoprotein E phenotype and age in men. These studies explain much of the variability that individuals show in lipoprotein changes, especially in the more desirable changes in cholesterol transport in HDL2, in response to eating saturated fat and cholesterol. |
| Body mass and weight as indicators for cholesterol screening Majeroni, B. A., G. Smallen, et al. (1992), J Fam Pract 35(5): 537-9. Abstract: BACKGROUND. Universal screening of serum cholesterol levels in adults has been recommended but not achieved. We were interested in factors that affected screening rates, and whether obese patients were more likely to have elevated cholesterol levels than other patients in our practice. METHODS. A sequential sample of charts was reviewed for height, weight, race, sex, diagnosis of hypertension or diabetes, and evidence of cholesterol screening. RESULTS. Of 604 adult patients, 32% had serum cholesterol measurements. No correlation was found between weight or body mass index and cholesterol levels. Patients with hypertension or diabetes were more frequently screened. Sex and race did not influence screening rates. CONCLUSIONS. In this population neither weight nor body mass index was associated with elevated serum cholesterol levels, suggesting that screening must be offered without regard to level of obesity in order to find those patients who will benefit from intervention. |
| Body weight and low-density lipoprotein cholesterol changes after consumption of a low-fat ad libitum diet Schaefer, E. J., A. H. Lichtenstein, et al. (1995), Jama 274(18): 1450-5. Abstract: OBJECTIVE--To assess the effects of a diet restricted in fat, saturated fat, and cholesterol, under weight-maintenance and ad libitum conditions on body weight and plasma lipid levels in hypercholesterolemic subjects. DESIGN--Dietary intervention study. SETTING AND PARTICIPANTS--Twenty-seven free-living, healthy middle-aged and elderly men (n = 13, age range, 41 to 81 years) and women (n = 14, age range, 52 to 79 years) with moderate hypercholesterolemia (low-density lipoprotein cholesterol LDL-C > or = 3.36 mmol/L 130 mg/dL) participated in the study. INTERVENTION--Subjects underwent three dietary phases. First, subjects were provided with a diet similar to the average US diet (baseline diet; 35.4% total fat, 13.8% to 14.1% saturated fat, and 30 to 35 mg/1000 kJ 128 to 147 mg/1000 kcal cholesterol). During the second dietary phase, subjects consumed a low-fat diet (15.1% total fat, 5.0% saturated fat, 17 mg/1000 kJ 73 mg/1000 kcal cholesterol). During the baseline and low-fat diet phases, which lasted 5 to 6 weeks each, the energy intake was adjusted to keep body weight constant. During the third diet phase (low-fat ad libitum diet) subjects were given the same low-fat diet for 10 to 12 weeks, but could adjust their intake between 66% and 133% of the energy required to maintain body weight. MAIN OUTCOME MEASURES--Body weight and plasma lipid levels. RESULTS--Consumption of the low-fat diet under weight-maintenance conditions had significant lowering effects on plasma total cholesterol (TC), LDL-C, and high-density lipoprotein cholesterol (HDL-C) levels (mean change, -12.5%, -17.1%, and -22.8%, respectively). This diet significantly increased plasma triglyceride levels (+47.3%) and the TC/HDL-C ratio (+14.6%). In contrast, consumption of the low-fat ad libitum diet was accompanied by significant weight loss (3.63 kg), by a mean decrease in LDL-C (124.3%), and by mean triglyceride levels and TC/HDL-C ratio that were not significantly different from values obtained at baseline. CONCLUSIONS--Our results indicate that a low-fat ad libitum diet promotes weight loss and LDL-C lowering without adverse effects on triglycerides or the TC/HDL-C ratio in middle-aged and elderly men and women with moderate hypercholesterolemia. |
| Body weight gain is correlated with serum cholesterol at 8 weeks of age in pigs selected for four generations for low or high serum cholesterol Pond, W. G., H. J. Mersmann, et al. (1993), J Anim Sci 71(9): 2406-11. Abstract: We determined the relationship of BW at birth, weaning (4 wk of age), and 8 wk of age to serum total cholesterol (C), high-density lipoprotein-cholesterol (HDL-C), and triglycerides (TG) at 8 wk of age in pigs, from the fourth generation that had been selected for low (10 litters, 75 pigs, LC) or high (10 litters, 63 pigs, HC) C at 8 wk of age. Mean C concentration at 8 wk of age was 81 +/- 30 mg/dL for LC groups and 136 +/- 19 mg/dL for HC groups. Serum C, HDL-C, and TG concentrations were not correlated with birth weight, suggesting that the physiological factors that may cause reduced weight gain in older animals are not operative in newborn pigs. All three constituents were correlated (P <.05) with BW at weaning and at 8 wk. However, only 4% of the variation in weight at weaning and 7% at 8 wk could be explained by a relationship with serum TG. There was a positive correlation between C and BW at 8 wk (r =.46, P <.05), which was apparent within the subgroups of LC and HC females and LC males (r =.46.48.68, respectively); the correlation was low (r =.26) in HC males. |
| Body weight modulates cholesterol metabolism in non-insulin dependent type 2 diabetics Simonen, P. P., H. Gylling, et al. (2002), Obes Res 10(5): 328-35. Abstract: OBJECTIVE: Cholesterol metabolism was studied in 64 subjects with type 2 diabetes who had body weight ranging from normal to obese, to find out whether weight interferes with cholesterol metabolism in diabetes. RESEARCH METHODS AND PROCEDURES: Cholesterol absorption was measured with peroral isotopes and by assaying serum plant sterol and cholestanol to cholesterol ratios, cholesterol synthesis with sterol balance, and measuring serum cholesterol precursor ratios. RESULTS: The study population was divided into normal-weight (body mass index, 24.1 +/- 0.4 kg/m2; mean +/- SEM; n = 20) and obese (31.0 +/- 0.5 kg/m2; n = 44) groups. Despite similar serum cholesterol and blood glucose values, fecal neutral sterol excretion, cholesterol and bile acid synthesis, cholesterol turnover (1649 +/- 78 vs. 1077 +/- 52 mg/d; p < 0.001), and serum cholesterol precursors were higher, and cholesterol absorption % (32 +/- 1 vs. 40 +/- 2%; p < 0.05), serum cholestanol, and plant sterols were lower in the obese vs. the non-obese groups. Serum sex hormone-binding globulin was positively associated with variables of cholesterol absorption, whereas blood glucose, serum insulin, and body mass index were associated with variables of cholesterol synthesis. In multiple stepwise regression analysis, cholesterol absorption percentage (R2 = 24%) and body mass index (R2 = 15%) were the only variables explaining the variability of cholesterol synthesis. DISCUSSION: Body weight, through its entire range, regulates cholesterol metabolism in type 2 diabetes such that with increasing insulin resistance, cholesterol absorption is lowered and cholesterol synthesis increased. |
| Body, abdominal fat, and testes weights, and line by sex interactions in Japanese quail divergently selected for plasma cholesterol response to adrenocorticotropin Marks, H. L. and K. W. Washburn (1991), Poult Sci 70(12): 2395-401. Abstract: Line by sex interactions of BW, abdominal fat, testes weight, and plasma cholesterol were investigated in two Japanese quail lines. High (H-PCHOL) and low (L-PCHOL) quail lines had been developed by 18 generations of divergent selection for plasma cholesterol response to adrenocorticotropin (ACTH). Quail were from Generation 28 breeders maintained under a normal environment with no exposure to exogenous ACTH after Generation 18. Quail from growth-selected lines were also used to examine relationships between BW and plasma cholesterol. Body weights of H-PCHOL quail were significantly (P less than or equal to.05) heavier than BW of L-PCHOL quail at 2 and 4 wk of age. However, at 8, 16, and 28 wk BW were similar. Quail from long-term, growth-selected lines were observed to have plasma cholesterol levels similar to those of control lines. Therefore, early BW changes in H-PCHOL and L-PCHOL lines may not be related to plasma cholesterol changes. At 2 and 4 wk, male and female plasma cholesterol values were similar in the H-PCHOL and L-PCHOL lines, however, at 8 and 16 wk males had higher values than females in the H-PCHOL line, and females had higher values than males in the L-PCHOL line. Because interactions were present only after sexual maturity was reached, sex hormones may be involved in the expression of these interactions. Quail in the L-PCHOL line were observed to have significantly (P less than or equal to.05) more abdominal fat and significantly (P less than or equal to.05) smaller testes than quail in the H-PCHOL line. |
| Boiled coffee does not increase serum cholesterol in gerbils and hamsters Mensink, R. P., P. L. Zock, et al. (1992), Z Ernahrungswiss 31(1): 82-5. Abstract: In contrast to drip filter coffee, boiled coffee increases the serum cholesterol level in man. To identify the substance(s) responsible for this effect, it is necessary to find an animal model sensitive to boiled coffee. In this study, three groups of 20 male gerbils and three groups of six male hamsters were fed a control diet or a control diet supplemented with either freeze-dried boiled coffee or freeze-dried filtered coffee. At the end of the 5-week feeding period serum cholesterol levels were not different in either species fed the different diets. These results suggest that these animal species are not sensitive to boiled coffee, or that the cholesterol-raising factor in boiled coffee is lost during the process of freeze-drying. |
| Boiled coffee fails to raise serum cholesterol in hamsters and rats Beynen, A. C., M. P. Weusten-Van der Wouw, et al. (1996), Br J Nutr 76(5): 755-64. Abstract: Boiled coffee contains the lipid compounds cafestol and kahweol, which raise cholesterol strongly in man. These lipids are retained by paper filters. In a search for an animal model for the effect of coffee lipids on serum cholesterol concentrations, we fed hamsters (Mesocricetus auratus) and rats on mash diets consisting of a purified base diet and either boiled water, unfiltered boiled coffee or filtered boiled coffee. After a feeding period of 8 weeks there was no statistically significant effect of unfiltered boiled coffee on serum total cholesterol and triacylglycerol concentrations in either the hamsters or the rats. The level of serum cholesterol did respond predictably to the addition of cholesterol and/or saturated fatty acids to the diet. The lack of effect of unfiltered boiled coffee in the hamsters and the rats, when compared with the previously reported activity in humans, could not be explained by dosage, duration of treatment, mode of administration or by insufficient statistical power. It is concluded that hamsters and rats are insensitive to unfiltered boiled coffee and thus are unsuitable models for investigating its hypercholesterolaemic effect. |
| Bone-resorbing activity from cholesterol-exposed macrophages due to enhanced expression of interleukin-1alpha Sjogren, U., H. Mukohyama, et al. (2002), J Dent Res 81(1): 11-6. Abstract: The presence of cholesterol crystals, macrophages, and foreign giant cells has been associated with impaired bone healing of periapical lesions. Therefore, we investigated whether macrophages exposed to cholesterol crystals can release factors changing the activity of bone-resorbing osteoclasts. Mouse peritoneal macrophages treated with cholesterol crystals in vitro produced factor(s) that stimulated the release of 45Ca and 3H from mouse calvariae pre-labeled with 45Ca(CaCl2) or 3H-proline, respectively. No bone-resorbing activity was released by epithelial cells, fibroblasts, or osteoblasts exposed to cholesterol crystals. Interleukin-1 receptor antagonist protein and antiserum neutralizing mouse interleukin-1alpha (IL-1alpha) inhibited 45Ca release induced by cholesterol-activated macrophages. The addition of cholesterol to the macrophages augmented the release of IL-1alpha protein and the expression of IL-1alpha mRNA. These findings indicate that frustrated phagocytosis by macrophages exposed to cholesterol crystals results in release of factors stimulating osteoclastic bone resorption, primarily due to increased transcription of the IL-1alpha gene. |
| Both free and esterified plant sterols reduce cholesterol absorption and the bioavailability of beta-carotene and alpha-tocopherol in normocholesterolemic humans Richelle, M., M. Enslen, et al. (2004), Am J Clin Nutr 80(1): 171-7. Abstract: BACKGROUND: Plant sterols reduce cholesterol absorption, which leads to a decrease in plasma and LDL-cholesterol concentrations. Plant sterols also lower plasma concentrations of carotenoids and alpha-tocopherol, but the mechanism of action is not yet understood. OBJECTIVES: The aims of this clinical study were to determine whether plant sterols affect the bioavailability of beta-carotene and alpha-tocopherol in normocholesterolemic men and to compare the effects of plant sterol esters and plant free sterols on cholesterol absorption. DESIGN: Twenty-six normocholesterolemic men completed the double-blind, randomized, crossover study. Subjects consumed daily, for 1 wk, each of the following 3 supplements: a low-fat milk-based beverage alone (control) or the same beverage supplemented with 2.2 g plant sterol equivalents provided as either free sterols or sterol esters. During this 1-wk supplementation period, subjects consumed a standardized diet. RESULTS: Both of the milks enriched with plant sterols induced a similar (60%) decrease in cholesterol absorption. Plant free sterols and plant sterol esters reduced the bioavailability of beta-carotene by approximately 50% and that of alpha-tocopherol by approximately 20%. The reduction in beta-carotene bioavailability was significantly less with plant free sterols than with plant sterol esters. At the limit of significance (P = 0.054) in the area under the curve, the reduction in alpha-tocopherol bioavailability was also less with plant free sterols than with plant sterol esters. CONCLUSIONS: Both plant sterols reduced beta-carotene and alpha-tocopherol bioavailability and cholesterol absorption in normocholesterolemic men. However, plant sterol esters reduced the bioavailability of beta-carotene and alpha-tocopherol more than did plant free sterols. |
| Both sphingolipids and cholesterol participate in the detergent insolubility of alkaline phosphatase, a glycosylphosphatidylinositol-anchored protein, in mammalian membranes Hanada, K., M. Nishijima, et al. (1995), J Biol Chem 270(11): 6254-60. Abstract: SPB-1, a Chinese hamster ovary cell variant defective in serine palmitoyltransferase activity for sphingolipid synthesis, provides a useful system for studying the effects of sphingolipids and/or cholesterol deprivation on cellular functions and membrane properties. To investigate whether there was an interaction among sphingolipids, cholesterol, and glycosylphosphatidylinositol (GPI)-anchored proteins in biological membranes, we introduced human placental alkaline phosphatase (PLAP) in SPB-1 and in wild type cells by stable transfection and examined the effects of sphingolipid and/or cholesterol deprivation on the solubility of PLAP in Triton X-100. Although the PLAP solubility of the membranes isolated from the control cells in Triton X-100 was only 10%, deprivation of sphingolipid and cholesterol further enhanced the solubility, which reached 50% when both sphingolipids and cholesterol were deprived. The enhanced solubility was suppressed to the control level by metabolic complementation with exogenous sphingosine and cholesterol. The sphingolipid and cholesterol content of the isolated membranes changed independently, eliminating the possibility that sphingolipid deprivation induced a reduction in cellular cholesterol and enhanced PLAP solubility and vice versa. It was also unlikely that the enhanced solubility was due to structural changes in PLAP molecules since, regardless of sphingolipid and cholesterol deprivations, almost all PLAP had the GPI-anchor moiety and there were no differences in the apparent molecular weight of the protein in supernatant and precipitate fractions of the detergent-treated membranes. In addition, the expression level of caveolin in the isolated membranes was not significantly affected by sphingolipids and/or cholesterol depletion. These results indicated that both sphingolipids and cholesterol were involved in the PLAP insolubility and suggested that these lipids coordinately played a role in formation of Triton X-100-resistant complexes. |
| Bovine gallbladder mucin accelerates cholesterol monohydrate crystal growth in model bile Afdhal, N. H., N. Niu, et al. (1993), Gastroenterology 104(5): 1515-23. Abstract: BACKGROUND: Gallbladder mucin accelerates cholesterol crystal nucleation, an early step in the pathogenesis of gallstones. To examine the role of gallbladder mucin in postnucleation gallstone maturation, the influence of mucin on cholesterol monohydrate crystal growth was studied in a novel model system. METHODS: Cholesterol crystals of a uniform size were incubated in model biles at 37 degrees C with varying cholesterol saturation indices. Crystal size was quantitated by measuring the width and length of individual crystals under polarizing light microscopy and calculating average crystal area. RESULTS: Crystal growth was dependent on the degree of cholesterol supersaturation of bile. Bovine gallbladder mucin (0.5-8 mg/mL) accelerated crystal growth in supersaturated model bile in a concentration- and time-dependent fashion compared with control incubations with bovine serum albumin or model bile alone (P < 0.05). Cholesterol crystal growth was accompanied by a progressive decrease in cholesterol saturation and an increase in total cholesterol crystal mass. Crystal growth was also accompanied by a decrease in total crystal number, suggesting net transfer of cholesterol to larger crystals. CONCLUSIONS: The acceleration of cholesterol crystal growth by gallbladder mucin may be of pathophysiological importance in the postnucleation maturation of cholesterol gallstones. |
| Bovine lactoferrin reduces plasma triacylglycerol and NEFA accompanied by decreased hepatic cholesterol and triacylglycerol contents in rodents Takeuchi, T., H. Shimizu, et al. (2004), Br J Nutr 91(4): 533-8. Abstract: In the present study we examined whether oral administration of bovine lactoferrin (bLF) reduces plasma or hepatic triacylglycerol and cholesterol in mice. When bLF mixed with a standard commercial diet (10 g/kg) was given to mice for 4 weeks, plasma triacylglycerol and NEFA decreased, while plasma HDL-cholesterol levels increased (P<0.01). These changes in plasma lipid profiles were accompanied by significant decreases in hepatic cholesterol and triacylglycerol contents. When mice were fed a high-fat diet containing 300.0 g lard, 10.0 g cholesterol and 2.5 g bovine bile powder/kg for 4 weeks, bovine LF did not have any significant effects on plasma or hepatic cholesterol and triacylglycerol concentrations. Furthermore, bLF had no significant effects on faecal excretion of total bile acids in mice. Interestingly, bLF showed a suppressive effect on the lymphatic triacylglycerol absorption in chronically treated rats. We conclude that bLF has a beneficial effect on plasma cholesterol levels and retards hepatic lipid accumulation in mice fed a standard diet. |
| Bovine oviductal fluid components and their potential role in sperm cholesterol efflux Ehrenwald, E., R. H. Foote, et al. (1990), Mol Reprod Dev 25(2): 195-204. Abstract: Bovine oviductal fluid (OF) was collected and analyzed throughout the estrous cycle, and the capacity of the protein and lipoprotein components to support cholesterol efflux from bovine sperm was evaluated. Blood was collected and assayed for progesterone (P4) to monitor the estrous cycle. Protein and lipoprotein separation was achieved by density gradient centrifugation. Two major bands were identified. The first (1.056 less than delta 20 less than 1.140 g/ml) corresponded to bovine and rabbit plasma high-density lipoprotein (HDL) based on distribution in the density gradient and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The second band (1.235 less than delta 20 less than 1.243 g/ml) consisted predominantly of oviductal fluid albumin (OFA). Oviductal fluid protein concentration increased as serum P4 decreased around the time of estrus. Mean OF protein concentration was 21.3 mg/ml when serum P4 was lower than 0.5 ng/ml and 6.9 mg/ml when serum P4 was greater than 0.5 ng/ml. An inverse log relationship was found between HDL protein concentration and serum P4. Unesterified cholesterol (UC), cholesteryl ester, and phospholipid (PL) content of HDL for HDL protein concentrations of 3-56.1 micrograms/ml were 1.35-46.2 micrograms/ml, 1.91-44.48 micrograms/ml, and 1.69-59.8 micrograms/ml, respectively. Phosphatidylcholine and -ethanolamine were the major PLs present in the HDL fraction and their molar ratio (4:1 mol/mol) was relatively constant through the estrous cycle. The OFA fraction of the same samples accounted for more than 90% of total protein and for most of the variation in OF protein. To determine the ability of OF components to serve as sperm cholesterol acceptors, OF samples were incubated 1:1 (v/v) with and without 4 X 10(8) bovine sperm in 1.0 ml of modified Tyrode's solution and OF for 2 hr at 39 degrees C. After incubation, HDL and OFA fractions were isolated and analyzed for changes in protein and lipid content. After OF, samples were incubated with sperm, an increase in UC was found in the HDL fractions. UC in HDL increased by 12.1 +/- 1.0 micrograms/ml (means +/- SE) when serum P4 was less than or equal to 0.5 ng/ml. For samples corresponding to higher serum P4, the increase in UC was 3.60 +/- 0.89 micrograms/ml. Values for UC in HDL were corrected for the contribution of UC from OFA of OF samples. Cholesterol efflux from sperm has been implicated in the process of sperm capacitation. These results indicate that HDL from OF is elevated during the follicular phase of the estrous cycle and can serve as an acceptor for bovine sperm cholesterol. |
| Brain cholesterol and phospholipid levels in cyproheptadine treated albino rats Kabi, B. C., Y. N. Rao, et al. (1993), Indian J Physiol Pharmacol 37(2): 165-6. Abstract: Effect of different doses (2.5 mg, 5 mg, 10 mg and 40 mg/kg), s.c., for 2 weeks, of cyproheptadine (CYP) on brain cholesterol and phospholipid of albino rats was investigated. Cyp. 2.5 mg/kg, showed increase in brain cholesterol and phospholipid contents whereas other doses caused a decrease in phospholipid level. |