HALEY, S*; DEARING, M.D.; University of Utah: Detoxification of plant secondary compounds by woodrat herbivores, genus Neotoma.

Mammalian herbivores routinely consume diets laden with toxins, yet the way in which wild herbivores detoxify plant secondary compounds is largely unknown. We took a pharmacological approach to understanding how a specialist (Neotoma stephensi) and generalist (Neotoma albigula) herbivore, processes the same dietary toxins. We investigated the detoxification mechanisms of N. stephensi and N. albigula on a 25% juniper diet which contains plant secondary compounds and a toxin free diet as well as specialists on a 70% juniper diet. We assayed for enzyme activity of 2 major groups of detoxification enzymes: cytochrome P450s and UDP-glucuronosyltransferases (UGT). The results indicate that N. stephensi and N. albigula on a 25% juniper diet induce cytochrome P450s and glucuronidation. Specialists and generalists induce cytochrome P450 content to similar degrees. Furthermore, specialists on a 70% juniper diet did not further induced cytochrome P450s. N. stephensi on juniper diet had significantly higher levels of UGT activity compared to generalist. The results indicate that the detoxification system of N. stephensi and N. albigula is induced by diet. Moreover, specialist herbivore, N. stephensi, appears to rely more on glucuronidation than generalist, N. albigula, to detoxify the same plant secondary compound.