Methyl-substitution of benzene and toluene in preparations of human bone marrow

The metabolism of benzene and toluene was investigated in preparations of human bone marrow incubated with S-adenosyl-L-methionine. Benzene undergoes a methyl-substitution reaction to yield toluene as a metabolite. Furthermore, toluene undergoes methyl-substitution in preparations of human bone marrow incubated with S-adenosyl-L-methionine to yield o-xylene, m-xylene, and p-xylene. Metabolites were detected by gas chromatography and mass spectroscopy. No metabolism of either benzene or toluene was detected when a boiled bone marrow preparation was used in the incubation, demonstrating the enzymatic nature of the S-adenosyl-L-methionine dependent methylation of both benzene and toluene.     

Effects of cannabinoids on progesterone release in cultures of rat luteal cells

This study investigated the direct effects of tetrahydrocannabinols (THC) on progesterone release by cultured rat luteal cells, as a function of dose and time. During a 24-h incubation, the level of progesterone in the culture medium was decreased by 35% and 60% in the presence of 1 microM 11-OH-delta 9-THC and 8 beta-OH-delta 9-THC, respectively, when compared with control cultures. Dose-response analysis revealed that 8 beta-OH-delta 9-THC inhibited progesterone levels at 0.1 microM but not at lower concentrations. The action of 8 beta-OH-delta 9-THC was rapid in onset and a significant effect could be observed as early as 2 h following the addition of the cannabinoid. While luteinizing hormone (LH, 1 microgram/ml) significantly enhanced progesterone release in the culture medium over the respective control levels, this action of LH was dramatically suppressed by the concomitant presence of 8 beta-OH-delta 9-THC at 2, 4 and 24 h in separate experiments. Moreover, the increase in the level of progesterone in the culture medium induced by 8-bromo-cyclic AMP was also attenuated by the concomitant presence of 8 beta-OH-delta 9-THC in the cultures. These results further substantiate a direct action of cannabinoids on the steroidogenic function of the corpus luteum, and that it involves at least some step(s) distal to the LH-sensitive adenylate cyclase system.     

Effect of various substituents in the 6-position on the relative carcinogenic activity of a series of benzo[a]pyrene derivatives

To test the hypothesis that polycyclic aromatic hydrocarbons capable of being converted to a reactive ester of the mesohydroxymethyl metabolite would be carcinogenic, a series of 6-substituted derivatives of benzo[a]pyrene (B[a]P) were tested for carcinogenicity in Sprague-Dawley rats by subcutaneous injection of the compound in sesame oil on alternate days for 30 doses. At the 0.2-μmol dose level B[a]P, 6-acetoxymethyl(6-AcOCH₂)B[a]P, 6-hydroxymethyl(6-HOCH₂)B[a]P, 6-methyl(6-CH₃)B[a]P and 6-benzoyloxymethyl(6-BzOCH₂)B[a]P were nearly equipotent, 6-formyl(6-OCH)-and 6-chloromethyl(6-ClCH₂)B[a]P were less active, and 6-methoxymethyl (6-MeOCH₂)B[a]P was inactive. At lower doses the order of potency was estimated to be: 6-AcOCH₂- = 6-HOCH₂- = or > B[a]P > 6-CH₂- > 6-BzOCH₂- > 6-ClCH₂- > 6-OCH- > 6-BrCH₂B[a]P. Incubation of these compounds in the presence of cofactors or cofactors plus a microsomal preparation of rat subcutis indicated that enzymic activation was necessary for metabolism to highly polar products and for conversion of 6-AcOCH₂-, 6-BzOCH₂- and 6-OCHB[a]P to 6-HOCH₂B[a]P. The halomethyl compounds were converted to 6-HOCH₂B[a]P in the absence of enzyme by hydrolysis. 6-MeOCH₂B[a]P was unchanged in this system. These observations are consistent with the foregoing hypothesis with regard to derivatives of B[a]P and demonstrate that compounds of this series that are capable of conversion to the 6-HOCH₂-derivatives are carcinogenic.