Molecular Pharmacology, Vol 9, 163-171, Copyright © 1973 by the American Society for Pharmacology and Experimental Therapeutics

Action of Levallorphan: Macromolecular Synthesis and Cell Division

¹ Department of Zoology, University of Toronto, Toronto, Ontario, Canada

Tetrahymena pyriformis GL, an amicronucleate ciliate, was maintained axenically in a Proteose-Peptone medium and division was synchronized by the multiple heat shock method. Levallorphan, a non-narcotic analogue of morphine, was investigated over a range of concentrations from 0.01 to 5.0 mM for its effect on cell division and macromolecular synthesis. Increase in division delay and decrease in RNA, DNA, and protein synthesis were all determined to be directly related to the dose. Levallorphan reduced the amount and specific activities of polyribosomes labeled with [³H]uridine and [¹⁴C]amino acids. The synthesis of all species of RNA was reduced by levallorphan treatment, with ribosomal RNA being the most sensitive. These data support the proposal that the reduction in macromolecular synthesis following levallorphan treatment is directly related to the drug-induced division delays.

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ACKNOWLEDGMENTS The authors wish to express their sincere thanks to Dr. Daniel McClean and Mrs. H. Laurence for their technical assistance.