Absence of Developmental Effects in CF-1 Mice Exposed to Aspartame in Utero

Abstract

Aspartame (L-aspartyl-L-phenylalanine methyl ester) is a widely used high potency dipeptide sweetener. Developmental toxicology studies have been performed in several species documenting no effects of high doses of aspartame. Recently, a study by Mahalik and Gautieri ((1984) Res Commun. Psychol Psychiatry Behav. 9, 385–403) reported a delay in the achievement age for the visual placing response in mice pups after maternal administration of high dosages of aspartame during late gestation. In the present study developmental parameters were determined in offspring of CF-1 mice after maternal administration of aspartame at 500, 1000, 2000, and 4000 mg/kg body wt by oral gavage. Aspartame was administered on Days 15 through 18 of gestation. Maternal body weight, food consumption, gestation length, reproductive indices, and litter size were not affected by aspartame treatment. In the pups, body weights, negative geotaxis, and surface and midair righting reflexes were not altered by treatment. There was no delay in the development of the visual placing response regardless of the method employed for assessment (grid or rope) or the manner by which the data were analyzed. There were also no changes in time of eye opening, reflex pupil closure, and ophthalmoscopic examination in the offspring. Thus, neither physical nor functional development was altered in mice after in utero exposure to extremely large dosages of aspartame. More specifically, in utero exposure to aspartame did not affect the development of the visual system in mice.