1983 Merit award

rOXlCOLOCY

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PHARMACOLOGY

70, 169- 170 ( 1983)

ANNOUNCEMENTS 1983

Merit

Award

PERRY J. GEHRING

The Merit Award is presented to a member of the Society of Toxicology in recognition of a distinguished career in Toxicology. The recipient of the 1983 Merit Award, Dr. Perry J. Gehring, has made substantial contributions to the field of toxicologic mechanisms. His work has been both general and specific, and it has provided an understanding of toxic chemical effects on the blood, liver, eyes, kidneys, and other target organs. Dr. Perry J. Gehring, Vice President of Agricultural Chemicals, Research and Development and Director of Health and Environmental Sciences USA, at Dow Chemical USA, is a native of Yankin, South Dakota and received B.S., D.V.M., and Ph.D. degrees from the University of Minnesota. Dr. Gehring joined Dow Chemical in 1965 as a Research Pharmacologist in the Toxicology Research Laboratory. He became a member of the faculty of the Department of Pharmacology at Michigan University in 1968 as an Associate Professor and returned to Dow Chemical Company as Assistant Director of the Toxicology Research Laboratory in 1970. He was named Director of the Laboratory in 1973 and in 1978 became Director of Health and Environmental Sciences, USA. Dr. Gehring was the President of the Society of Toxicology during 1980- 198 1. From the work of Dr. Gehring, an emphasis on the relationship of pharmacokinetics to chemical toxicity is found. This focus has provided the knowledge required to 169

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ANNOUNCEMENTS

intelligently predict toxic effects in man from high dose observations in animals. Thus pharmacokinetics and macromolecular mechanism have been a centerpiece of his work. Chemical workers exposed to vinyl chloride were found to have an increased incidence of hepatic hemangiosarcoma, a rare tumor. Observations in Sprague-Dawley rats exposed to vinyl chloride by inhalation confirmed a relationship between the chemical and angiosarcomas; however, in the rat the dose-response curve for these tumors was steepest at the lower administered doses. Consequently, linear extrapolation procedures for risk assessment generated anti-conservative low dose risk estimates. The recipient recognized that vinyl chloride was metabolically activated to produce a carcinogenic metabolite, and that the reaction proceeded in accordance with Michaelis-Menten kinetics, that is, the process was saturable. When the incidence of tumors in rats was plotted against the amount of active metabolite actually delivered to the target site, a much better dose-response relationship, linear in the low dose region, was found. Consequently, the estimated risk associated with low doses by a multistage risk assessment mode1 was consistent with the data and fit well with the known tumor incidence caused by vinyl chloride in man. The importance of defining the delivered dose of an active chemical at the site of chemical effect was demonstrated; this concept provides a basis for toxicology to be a better predictive science. It is fitting that the Society of Toxicology recognize Dr. Perry J. Gehring by presenting him this Award.