UMASS.

UNIVERSITY of MASSACHUSETTS NORTHEAST REGIONAL

School of Public Health & Health Sciences ENVIRONMENTAL |
Environmental Health Sciences Department PUBLIC HEALTH CENTER
Morrill Science Center 1, N344 voice: 413.545.3164
Amherst, MA 01003-5712 fax: 413.545.4692
e-mail: nrephc@schoolph.umass.edu
May 22, 2000

Dr. Joshua Lederberg

The Rockefeller University
1230 York Avenue

New York, NY 10021-6399

Dear Dr. Lederberg:

Thank you very much for your interest in our work on hormesis. I am
enclosing a package of articles that I hope you will find of interest, especially
the recent issue of Human and Experimental Toxicology which contains our
historical assessment of hormesis and the evolution of the dose-response. In
addition to the work included we have been evaluating the occurrence of
similar biphasic responses in pharmacological systems and find it to be
extremely common. In fact, we have obtained substantial information on
approximately 30 receptor systems, which display such biphasic dose-
responses where the mechanism is known for the basis of this response, at least
at the level of receptor and frequently with further detail. It is my belief that
many of these receptor systems are using concentration gradients of
endogenous agonists as a means to regulate biological activity. We have
developed manuscripts in these areas, exploring this relationship to the
hormesis phenomenon and hopefully I will be able to send you these once they
are finalized.

I would look forward to hearing from you concerning these
developments. I will also try to track down the other references that you
indicated.

Sincerely,

Edward J. Calabrese, Ph.D.
Professor of Toxicology

Director of the Northeast Regional
Environmental Public Health Center

EJC/psg

The University of Massachusetts is an Affirmative Action/Equal Opportunity Institution ® Printed on Recycled Paper