Cholesterol degradation

Mast, N., Norcross, R., Andersson, U. et al. Broad substrate specificity of human cytochrome P450 46A1 which initiates cholesterol degradation in the brain. Biochemistry 42 14284-14292, 2003. 

Implementation The GC-MS of the sample headspace finds no perfume compounds. The cream is found to be greater than 80-wt% organic matter. Pyrolysis-GC-MS identified significant levels of glucose polymers, which were confirmed by FTIR to be either cellulose or starch. The iodine test revealed that the glucose polymer was starch. Further GC-MS analysis did not find cholesterol, but did find trace levels of a cholesterol degradation product. 

A characteristic sign of hypothyroidism is a decrease in metabolic rate, with a reduction in calorigenic effect and defective thermoregulation. The elevated serum cholesterol level seen in hypothyroidism is the result of a decrease in cholesterol degradation that exceeds the decrease in cholesterol biosynthesis it reflects a... 

As well as 24-hydroxylase activity, CYP46A1 also shows 25- and 26-hydroxylase activity. Mast, N. et al., 2003, Broad Substrate Specificity of Human Cytochrome P45046A1 Which Initiates Cholesterol Degradation in the Brain, Biochemistry. 42 14284-92. 

Bile salts are biosurfactants naturally formed by cholesterol degradation in the liver. Bile acids are stored in the gall-bladder. After derivation with glycine or tauric acid, the sodium salts of the derivatives are essential in the digestion process to emulsify food triglycerides. The pancreatic lipase enzyme can only split emulsified fatty globules. 

Drzyzga O, Fernandez de las Heras L, Morales V, Navarro Llorens JM, Perera J (2011) Cholesterol degradation by Gordonia cholesterolivorans. Appl Environ Microbiol 77 4802 810... 

Mast N, Norcross R, Andersson U, Shou M, Na-kayama K, Bjorkhem I, Pikuleva lA (2003) Broad substrate specificity of human cytochrome P450 46A1 which initiates cholesterol degradation in the brain. Biochemistry 42 14284-14292 Bjorkhem I, Starck L, Andersson U, Lutjohann D, von Bahr S, Pikuleva I, Babiker A, Diczfalusy U (2001) Oxysterols in the circulation of patients with the Smith-Lemli-Opitz syndrome abnormal levels of 24S- and 27-hydroxycholesterol. J Lipid Res 42 366-371... 

Exercise was reported to increase cholesterol degradation, as measured by respiratory excretion of COa, in healthy male patients receiving 26 C cholesterol . ... 

Stated in terms of the reaction, cholesterol —> pregnenolone, upon which ACTH seems to have an effect, our problem may now be stated where is the enzymatic mechanism for cholesterol degradation located in the cell What is the cellular site of the active cholesterol which is utilized as a substrate for corticosteroid production Are substrate and enzyme separated in the cell If so, how do these components react, and what are the factors involved Detailed answers to these questions are not, as yet, available. However, N. Saba, working with the author, has opened the way toward a solution of the problems raised. With C cholesterol as substrate, it has been shown that adrenal homogenates... 

Besides their action on cholesterol biosynthesis, nicotinic acid and chloro-phenoxyisobutyrate (CPIB) could also interfere with cholesterol degradation. In fact, nicotinic acid enhances cholesterol side-chain oxidation by rat-liver mitochondria, an action shared by 3-pyridylacetic acid which has also been reported to have hypocholesterolaemic properties. 

Malinow, M.R. and Perley, A. The Effect of Physical Exercise on Cholesterol Degradation in Man. ... 

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