A newly described tripeptide, pyroGluHisGlyOh, which was reported to produce profound and long-term anorexia and weight loss in female mice, was initially tested in female rats. After total does of either 8, 16, or 32 μg SC of the peptide, administered across an eight day interval, there was no detectable effect on food intake, body weight, or estrous cycles of female rats. In a second study, we attempted to verify the anorexigenic potency of this peptide in mice. Total doses of 3.4 and 6.8 μg, injected across a 20 day period, had no effect on the food intake or body weight of S/W albino female mice. Thus, the anorexigenic potency of pyroGluHisGlyOH has yet to be established. © 1979.