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Biomedical subjects

E Hodgson

Publications and source records attributed to E Hodgson.

At least 109 records · Page 6Linked to original sources
PubMed1980

Induction of hepatic drug metabolizing enzymes in mammals by pesticides: A review.

The induction of drug metabolizing enzymes in mammals is summarized including both enzymes of the cytochrome P-450-dependent microsomal mixed function oxidase system and glutathione S-transferases. Particular emphasis is placed on the role of pesticides as inducers, the early work being summarized while investigations carried out at North Carolina States University are considered in greater detail. Finally, the possible significance of induction is considered.

Animals↗
PubMed1980

S-(O-ethyl phenylphosphonothionyl) glutathione; evidence for its formation in the in vitro metabolism of EPN in houseflies.

Double labelling experiments using [phenyl-14C], [2,6-p-nitro-phenyl-14C]- or, nonradioactive EPN with [35S]-, [glycine-3H]- or nonradioactive glutathione in the presence of the 100,000g supernatant fraction from the Rutgers strain of houseflies resulted in the formation of a radiolabelled conjugate. Hydrolysis of the [phenyl-14C] conjugate formed the phenyl-[14C]-phosphonothioic acid. The proposed structure of the conjugate is S-(O-ethyl phenylphosphonothionyl) glutathione. The conjugate is formed with racemic, (+), or (-) EPN. Structure activity studies indicate the following: a decrease in the electron withdrawing properties of the substituents on the O-p-nitrophenyl moiety results in a decrease in the formation of the conjugates; substituting the phenylphosphonothioic moiety with the ethyl-phosphonothioate, inhibits the formation of the corresponding conjugate' substituting the O-ethyl group with other alkyl groups did not effect the formation of the corresponding conjugate.

Abdomen↗
PubMed1979

The interaction of aliphatic analogs of methylene-dioxyphenyl compounds with cytochromes P-450 and P-420.

The spectra resulting from the interaction of a series of substituted dioxolanes with microsomal cytochromes P-450 or P-420, as well as purified cytochrome P-450, were measured. With the exception of dioxolane, 4-methyldioxolane and 4-ethyldioxolane, these compounds interacted with ferric cytochrome P-450 to give complexes exhibiting type I optical difference spectra, and, after incubation with NADPH, spectra with peaks at about 430 nm. These complexes, as well as those formed from dioxolanes in the presence of cumene hydroperoxide, inhibit the binding of CO to the cytochrome. Consideration of the known chemistry of dioxolanes, together with recent advances in the understanding of double Soret spectra, lead to a possible explanation for the differences between the spectra of dioxolanes and their aromatic analogs, the methylenedioxyphenyl compounds.

Animals↗
PubMed1978

Complexes of trivalent oxygenated phosphorus compounds with cytochrome P-450 and cytochrome P-420: the origin of double Soret spectra.

Trivalent oxygenated phosphorus ligands include alkyl and aryl phosphites, (RO)3P, phosphonites, (RO)2PR, and phosphinites, ROPR2. All such compounds tested, with the exception of triphenyl phosphite, interact with ferrous cytochrome P-450 and its denatured form, cytochrome P-420, to produce complexes having two peaks in the Soret region of their optical difference spectra. Careful evaluation of these spectra indicate that they arise for different reasons for each of the two cytochromes. Clear evidence shows that cytochrome P-450 is not denatured by these ligands. The high affinity of these ligands for heme iron is indicated by small Ks values. The experimental results are used to substantiate a theory of the origin of microsomal double Soret spectra and the nature of the environments available for microsomal cytochromes P-450 and P-420.

Animals↗
PubMed1978

The affinity of cytochrome P-450 for ethyl isocyanide: an explanation of double soret spectra.

The 2 pH dependent peaks formed in the Soret region by the treatment of reduced hepatic microsomes or purified cytochrome P-448 with ethyl isocyanide do not exhibit identical dependence on ethyl isocyanide concentration. This behavior and other facts regarding double Soret spectra can be explained by a simple expostulation involving lipophilic and corrdinate binding of pi-acceptor ligands.

Animals↗
PubMed1977

Complexes of stannous fluoride and other group IVB dihalides with mammalian hemoproteins.

Stannous fluoride, the widely used anticaries toothpaste additive, and other tin and germanium dihalides form complexes with hemoproteins such as hepatic cytochrome P-450, hemoglobin, and peroxidase. These complexes are characterized by visible spectra closely similar in shape, molar absorptivity, and absorbance maxima to those obtained with analogous complexes of carbon monoxide. Evidence is presented that the observed complexes are formed with uncharged MX2 or LMX2, moieties (where L is a neutral Lewis base, M is a metal, and X is a halogen) acting as pi-acceptor ligands.

Bromides↗
PubMed1977

An unusual effect of N-octylamine on the cytochrome b5 spectrum of insect and mammalian microsomes.

The addition of n-octylamine to microsomes prepared from the midgut of tobacco hornworn (Manduca sexta) larvae causes an unusual spectral interaction. The initial optical difference spectrum appears to be the sum of reduced cytochrome b5 and a type II difference spectrum of cytochrome P-450. This initial spectrum is unstable and diminishes in size, with a concurrent shift in peak (424 to 428 nm) and trough (409 and 392 to approx. 400 nm) positions, to yield a stable spectrum identical to the type II spectrum of cytochrome P-450. Thus, in addition to its interaction with cytochrome P-450, n-octylamine causes a reduction of cytochrome b5 which subsequently becomes reoxidized. The causal factor for this unusual spectral interaction occurs in the cytoplasm and appears to be protein-bound. It was also present in similar preparations from the tobacco budworm (Heliothis virescens) but not in those from rat or mouse liver or abdomens from insecticide-resistant or susceptible houseflies (Musca domestica). Microsomes from rat and mouse liver, but not those from housefly abdomens, exhibit similar unusual spectral interactions with n-octylamine when supplemented with the soluble factor from the hornworm.

Amines↗
PubMed1977

Hepatic mixed-function oxidase activity in mice treated with methylated benzenes and methylated naphthalenes.

Eight methylated benzene and five methylated naphthalene compounds were injected ip into adult male mice daily for 3 days. On the fourth day livers from control and treated mice were compared with regard to weight, microsomal N- and O-demethylase activity, and various spectral characteristics of microsomal cytochrome P-450. Three methylated benzenes and one methylated naphthalene produced significant increases in liver weight/body weight ratios, O-demethylation of p-nitroanisole, N-demethylation of aminopyrene, or a combination of these.

Animals↗