Publications

We studied the effects of recombinant murine tumor necrosis factor-alpha (TNF-alpha) on autoimmune disease in lupus-prone NZB/NZW F1 (B/W) mice. Treatment with TNF-alpha, begun after the onset of clinical disease, improved survival relative to control mice: at age 10 months, 92% of mice treated with TNF-alpha were alive compared with 42% of control mice (P less than 0.05). Administration of TNF-alpha delayed the progression of renal disease, but sustained therapy did not prevent the eventual development of severe nephritis. Despite the improvement in survival, treatment with TNF-alpha did not inhibit anti-dsDNA antibody production. However, it accelerated T lymphocytopenia and abolished natural killer cell activity. These observations suggest that TNF-alpha may retard murine lupus in B/W mice through effects on cellular rather than humoral mechanisms. Our findings also indicate that the beneficial effects of TNF-alpha cannot be sustained indefinitely by chronic therapy.

A cytochrome P-450 isozyme (Mr = 51,600) was purified to apparent homogeneity from hepatic microsomes of mice pretreated with cannabidiol (CBD), a major constituent of marijuana. The isozyme exhibited high pentoxyresorufin O-dealkylase, hexobarbital hydroxylase, and 16 alpha- and 16 beta-testosterone hydroxylase activities and formed a Fe+2-metyrapone complex, properties characteristic of the major hepatic cytochrome P-450s previously purified from phenobarbital (PB)-pretreated animals. In addition, the CBD-induced cytochrome P-450 was immunoreactive with an antibody raised against the major rat hepatic PB-inducible cytochrome P-450 and exhibited an NH2-terminal amino acid sequence greater than 90% homologous with that of the PB-inducible rat liver isozyme. Because of the many similarities between the CBD-induced isozyme and certain other isozymes previously purified from PB-pretreated animals, a cytochrome P-450 isozyme was purified from PB-pretreated mice by a chromatographic procedure similar to that employed for purification of the CBD-induced isozyme. The PB-inducible isozyme was indistinguishable from the CBD-inducible cytochrome P-450 on the bases of apparent molecular weight, absorption spectra, NH2-terminal amino acid sequence, peptide mapping, immunoreactivity, and catalytic activity. Although the CBD- and PB-inducible P-450 isozymes appear to be qualitatively very similar, PB appears to be a quantitatively better inducer of the isozyme. Thus, CBD exposure results in the induction of an isozyme that is refractory to CBD-mediated inactivation, thereby apparently altering the cytochrome P-450 isozymal composition of mouse hepatic microsomes.

Cannabidiol (CBD) has been shown to inhibit mouse hepatic mixed-function oxidations of several drugs after acute treatment, whereas repetitive treatment resulted in the restoration of drug-metabolizing capabilities. We have found that acute CBD treatment modestly decreased cytochrome P-450 content but markedly decreased hexobarbital hydroxylase, erythromycin N-demethylase, and 6 beta-testosterone hydroxylase activities. Repetitive CBD treatment, on the other hand, resulted in the restoration of cytochrome P-450 content as well as hexobarbital hydroxylase and erythromycin N-demethylase activities. However, after such repeated treatments a fresh dose of CBD can once again inactivate erythromycin N-demethylase activity but not hexobarbital hydroxylase activity. The resistance of hexobarbital hydroxylase to re-inactivation by CBD was paralleled by stimulation of pentoxyresorufin O-dealkylase activity and the appearance of a 50 kD protein that was immunoreactive to an antibody raised against rat hepatic cytochrome P-450b. CBD metabolism in vitro by microsomes prepared from such CBD-"induced" animals, resulted in a pattern of metabolites different from that observed from comparable incubations with liver microsomes from either untreated or phenobarbital-treated animals. Thus, it appears that CBD initially inactivates at least one cytochrome P-450 isozyme, but after repetitive CBD treatment, an isozyme is induced that is resistant to further re-inactivation by CBD. This isozyme appears to be immunochemically similar to, but somewhat functionally distinct from, the isozyme induced by phenobarbital treatment in mice.