Prenatal imprinting of postnatal specific appetites and feeding behavior.

Epigenetic influences on the fetus's genotype have been shown to occur during intrauterine life. Experimentally imposed extracellular dehydration in pregnant rats (a model for human hyponatremia caused by gravidic vomiting) brings about a dramatic enhancement of salt appetite not only in the dam, but also in offspring when they reach adulthood. This phenomenon has been verified in human newborn infants and adults whose mothers experienced nausea and/or vomiting during pregnancy. Alcohol consumption during pregnancy enhances its palatability for the offspring. Ingestion of olfactory test substances like anise or carrot by the mother during pregnancy gives rise to a preference for the same testants in the offspring. Under- or overnutrition in the pregnant mother appears to play a role in reprogramming the postnatal regulation of both feeding and fat reserves in offspring. Both maternal under- and overnutrition during pregnancy predispose the offspring to later development of obesity and type 2 diabetes mellitus. A careful examination of the systems concerned with the regulation of food intake, and the neurosubstances involved in such regulation, reveals some of the mechanisms by which maternal nutritional status can affect the offspring and their food-related behaviors.