Document Type

Dissertation - Open Access

Award Date


Degree Name

Doctor of Philosophy (PhD)

Department / School


First Advisor

Eugene W. Hamilton


Allopurinol, a potent inhibitor of xanthine oxidase in humans, was incorporated in the diets of differential grasshopper nymphs and adults and armyworm larvae. Uric acid contents of whole body homogenates decreased by highly significant rates. Feces uric acid decreased by highly significant rates in grasshopper nymphs and adults. Allopurinol also caused highly significant increases in mortality and inhibition of metamorphosis in study insects. These effects were not reversible by the addition of purine and pyrimidine bases, inosine, oxypurines, or uric acid. The effects were reversed by discontinuing application of allopurinol. Crude xanthine oxidase, assayed by measuring the reduction of NAD at 340 mu, from grasshoppers and armyworms was linear with respect to enzyme concentration. Allopurinol inhibition of xanthine oxidase was linear with respect to inhibitor concentration. Kinetic studies of crude grasshopper xanthine oxidase were used to evaluate the Michaelis-Menten constant for the oxidation of hypoxanthine (Km = 2.52 x 10-5 M), and to study xanthine oxidase inhibition (mixed) by allopurinol (Ki = 3.95 x 10-5 M). Electron microscopy of Malpighian tubule sections from grasshopper nymphs treated with allopurinol showed a reduction in size and number of vacuoles as compared to a control.

Library of Congress Subject Headings

Uric Acid -- Metabolism
Locusts -- Physiology
Armyworms -- Physiology



Number of Pages



South Dakota State University

Included in

Entomology Commons