Stability of suspensions of rat liver microsomes quick-frozen with liquid nitrogen and stored at -85°

Borton, Patricia; Carson, R. E.; Reed, Donald J.

doi:10.1016/0006-2952(74)90564-4

Cited by 18 publications

(2 citation statements)

References 8 publications

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“…Incubation Procedure. Microsomes were prepared according to the method of Borton et al (1974) and protein was determined by the method of Lowry et al (1951). Incubations contained in a final 3-ml volume: 0.1 M phosphate buffer (pH 7.4), 1.0 /umol of NADP, 25 µ of glucose-6-P, 1.2 units of glucose-6-P dehydrogenase, 1.8 µ of [cyc/o)zex>'/-l-14C]CCNU (12,600,000 dpm), and 2 mg of microsomal protein.…”

Section: Methodsmentioning

confidence: 99%

Microsomal monooxygenation of the carcinostatic 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea. Synthesis and identification of cis and trans monohydroxylated products

May¹,

Boose²,

Reed³

1975

Biochemistry

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Liver microsomal hydroxylation of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea was shown to occur on the cyclohexyl ring at positions 3 and 4. Four metabolites were isolated by selective solvent extraction and purifed by high-pressure liquid chromatography. cis-4-, trans-4-, cis-3-, and trans-3-OH derivatives of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea were synthesized and their chromatographic, mass spectral, and nuclear magnetic resonance characteristics matched those of the metabolites. The position of ring hydroxylation and the identity of each geometric isomer were established by nuclear magnetic resonance using a shift reagent in conjunction with spin decoupling techniques. Microsomes from rats pretreated with phenobarbital showed a sixfold increase in hydroxylation rate (19.5 vs. 3.3 nmol per mg per min). The induction was quite selective for cis-4 hydroxylation (19-fold); however, induction of trans-4 (threefold), cis-3 (threefold), and trans-3 (twofold) hydroxylation did occur. Quantitatively the cis-4-hydroxy metabolite was 67of the total product by phenobarbital-induced microsomes and 21% for normal microsomes. Microsomes from animals pretreated wit- 3-methyl-cholanthrene gave about the same rate and product distribution that normal microsomes gave. A mixture of 80% carbon monoxide-20% oxygen inhibited formation of all four hydroxy metabolites with the inhibition ranging from 55 to 78%.

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Section: Methodsmentioning

confidence: 99%

Microsomal monooxygenation of the carcinostatic 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea. Synthesis and identification of cis and trans monohydroxylated products

May¹,

Boose²,

Reed³

1975

Biochemistry

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“…At this temperature the loss of microsomal enzyme activity is kept to a minimum (Borton et al, 1974). Degranulation scheme RER portions were rapidly thawed.…”

Section: Generalmentioning

confidence: 99%