Male Sprague-Dawley rats were either treated with repeated ip injections of glucagon every 6 hr or partially starved. After 7 days of partial starvation or 5 days of glucagon injections, a time period shown previously to induce increased transport, all animals were sacrificed and a segment of jejunum was removed, fixed in formalin, sectioned, and dipped in Kodak NTB-2 liquid emulsion. After 8 weeks of exposure the autoradiographs were developed; assessments of villus height and crypt depth and measurements of length of the column of exposed grains were made in a calibrated microscope. The mean villus length in both semistarved and glucagon-treated groups was found to be significantly reduced (p less than 0.001) when compared to control animals. The crypt-to-villus ratio was found to be unaltered by either treatment modality. The rate of cell migration was diminished by both partial starvation and glucagon treatment, but only glucagon therapy was found to cause a significant (p less than 0.01) reduction in the rate of cell movement when compared to controls.