Brugia malayi: retinoic acid uptake and localization.

Retinoids play an important role in development and growth in a wide range of cells and tissues. The vitamin A status of the host appears to be a factor in the development of certain parasites, suggesting that vitamin A is an essential micronutrient for the proper growth and differentiation of parasites. To determine if exogenous retinoic acid is taken up by filarial parasites, adult male and female Brugia malayi were exposed to [3H] retinoic acid. Results indicated that retinoic acid was taken up by adult parasites in a specific and dose-dependent manner. In tissue sections of [3H] retinoic acid-labeled B. malayi, label was shown to localize to the cellular and not the acellular portions of the worms with high density of label associated with both early and late embryonic forms. The specific uptake and distribution of retinoic acid in B. malayi suggest that it may play a role in parasite growth and development.