Rat, cholesterol

Figure 4. Gas chromatograph-FID chromatogram of Wistar rat (A B) and atherosclerosis-susceptible Japanese quail (C D) aorta derivatized nonsaponifiables. (A) 0.05% low cholesterol, rat (B) 0.5% high cholesterol, rat (C) 0.05%, low cholesterol, quail (D) 0.5%o high cholesterol quail aorta. 1 = internal standard, 5a-cholestane 2 = cholesterol 3= 7 -hydroxycholesterol 4 = 7-ketocholesterol. Samples were analyzed according to Yuan et at. (69).

D-Mevalonic acid is the fundamental intermediate in the biosynthesis of the terpenoids and steroids, together classed as poly-isoprenoids. The biogenetic isoprene unit is isopentenyl pyrophosphate which arises by enzymic decarboxylation-dehydration of mevalonic acid pyrophosphate. D-Mevalonic acid is almost quantitatively incorporated into cholesterol synthesized by rat liver homogenates. 

Irradiated ergosterol was found not to be as antirachitic in the chick as in the rat, whereas the chick could be protected by direct kradiation. The provitamin in cholesterol was shown not to be ergosterol. Rygh (14) in 1935 found that 1 rat unit of cod Hver oil was 100 times more potent in chicks than 1 rat unit of vitamin D2. Brockmann (15) in 1936, prepared the pure crystalline 3,5-dinitrobenzoate derivative of vitamin D obtained from tuna Hver oil... 

Brewers and bakers dried yeasts are used as dietary supplements. They contribute some protein and trace minerals, and some B vitamins, but no vitamin C, vitamin B 2 or fat-soluble vitamins. The glucose tolerance factor (GTE) of yeast, chromium nicotinate, mediates the effect of insulin. It seems to be important for older persons who caimot synthesize GTE from inorganic dietary chromium. The ceU wall fraction of bakers yeast reduces cholesterol levels in rats fed a hypercholesteremic diet. 

Like the a2ole derivatives, it inhibits the biosynthesis of ergosterol. However, naftifine [65472-88-0] does not inhibit the cytochrome P-450 dependent C-14-demethylase, but the epoxidation of squalene. Squalene epoxidase cataly2es the first step in the conversion of squalene via lanosterol to ergosterol in yeasts and fungi or to cholesterol in mammalian cells. The squalene epoxidase in C. albicans is 150 times more sensitive to naftifine, C2 H2 N, than the en2yme in rat fiver (15). Naftifine is available as a 1% cream. 

Medicinal chemistry has frequently drawn inspiration and important new leads from the examination of natural products, and this was proven to be the case once more. In 1992, researchers at Merck and Glaxo announced, almost simultaneously, the independent discovery of the same new class of natural products from two different fungi. As a consequence, the same family of natural products has two names - the zaragozic acids (Merck)4 or the squalestatins (Glaxo).5 A typical member of the family, zaragozic acid A (squa-lestatin SI) (1) was shown to have a tremendous affinity for squalene synthase (K, = 79 pM for rat microsomal squalene synthase) and could even lower serum cholesterol levels in vivo in a population of marmosets.6... 

Evans, A.J. Hood, R.L. Oakenfull, D.G. Sidhu, G.S. (1992). Relationship between structure and function of dietary fibre a comparative study of the effects of three galactomannans on cholesterol metabolism in the rat. British Journal of Nutrition, Vol.68, No.l, (July 1992), pp. 217-229, ISSN 0007-1145. 

Moundras, C. Behr, S.R. Demigne, G. Mazur, A. Remesy, G. (1994). Fermentable polysaccharides that enhance fecal bile acid excretion lower plasma cholesterol and apolipoprotein E-rich HDL in rats. Journal of Nutrition, Vol. 124, No.ll, (November 1994), pp. 2179-2188, ISSN 0022-3166. 

Ellens, H., Morselt, H., and Scherphof, G. (1981). In vivo fate of large unilamellar sphingomyelin-cholesterol Liposomes after intraperitoneal and intravenous injection into rats, Biochim. Biophys. Acta. 674, 10-18. 

IKEDA I, IMASATO Y, SASAKI E, NAKAYAMA M, NAGAO H, TAKEO T, YAYABE F, SUGANO M (1992) Tea catechins decrease micellar solubility and intestinal absorption of cholesterol in rats. Biochim Biophys Acta. 1127 141-6. 

PARK Y B, JEON s M, BYUN s J, KIM H s, CHOI M s (2002) Absorption of intestinal free cholesterol is lowered by snpplementation of Areca catechu L. extract in rats. Life Sci. 70 1849-59. 

SEETHARAMIAH G s, CHANDRASEKHARA N (1990) Effect of gamma oryzanol on cholesterol absorption and biliary and fecal bile acids in rats. Ind J Med Res, 92 471-5. 

SUGANO M, ISHIWAKI N, NAKASHIMA K (1984) Dietary protein-dependent modification of serum cholesterol level in rats significance of Arginine/lysine ratio. rinw Nutr Metab, 28 192-9. 

Chloroform-methanol extracts of Borrelia burgdorferi were used for the identification of lipids and other related components that could help in the diagnosis of Lyme disease [58]. The provitamin D fraction of skin lipids of rats was purified by PTLC and further analyzed by UV, HPLC, GLC, and GC-MS. MS results indicated that this fraction contained a small amount of cholesterol, lathosterol, and two other unknown sterols in addition to 7-dehydrocholesterol [12]. Two fluorescent lipids extracted from bovine brain white matter were isolated by two-step PTLC using silica gel G plates [59]. PTLC has been used for the separation of sterols, free fatty acids, triacylglycerols, and sterol esters in lipids extracted from the pathogenic fungus Fusarium culmorum [60]. 

Hayden et al. 1990a), increased liver cholesterol in female rats exposed during gestation and lactation (Hayden et al. 1990b), and weight loss in pregnant rats (Saillenfait et al. 1989). 

TA Brasitus, R Dahiya, PK Dudeja, BM Bissonnette. Cholesterol modulates alkaline phosphatase activity of rat intestinal microvillus membranes. J Biol Chem 263 8592-8597, 1988. 

S Chapelle, M GiUes-BaiUien. Phospholipids and cholesterol in brush border and basolateral membranes from rat intestinal mucosa. Biochim Biophys Acta 753 269-271, 1983. 

Proulx [30] summarized the published lipid compositions of BBM isolated from epithelial cells from pig, rabbit, mouse and rat small intestines. Table 3.1 shows the lipid make-up for the rat, averaged from five reported studies [30], On a molar basis, cholesterol accounts for about 50% of the total lipid content (37% on a weight basis). Thus, the cholesterol content in BBM is higher than that found in kidney epithelial (MDCK) and brain endothelial cells (Table 3.1). Slightly different BBM lipid distribution was reported by Alcorn et al. [31] here, the outer (luminal) leaflet of the BBM was seen to be rich in sphingomyelin content, while the inner leaflet (cytosol) was rich in PE and PC. Apical (brush border) and basolateral lipids are different in epithelia. The basolateral membrane content (not reported by... 

Figure 14.13 8 13C values of the most abundant FAs and cholesterol in the Kwadgy Dan Ts inchj bone and skin samples (determined by GC C IRMS) compared with 813C values determined for the same compounds in individual s bone extracted from rats subjected to a pure C3 terrestrial diet, a 20% marine protein (tuna) diet and a 70% marine (tuna) diet (Jim, unpublished data)... 

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