The patterns of adaptive changes in intestinal glucose and amino acid absorption often parallel those in digestive enzymes during ontogeny, growth, and reproduction. Unlike the endocrine control of digestive enzymes, that for nutrient absorption is not well understood. Hence, the regulation of enzyme activity during development is first presented as a model for understanding how the related process of nutrienttransport may be coordinated by hormones. In particular, the effects of thyroid hormones and glucocorticoids are best known and illustrate how these mediators act independently in some cases and synergistically in others to produce the observed patterns of intestinal adaptation. Because there is information about these two classes of hormones and their actions in diverse vertebrate groups, I trace their known and suspected effects on nutrient uptake in mammals, birds, amphibians, and fishes.