Effect of prenatal or postnatal high-fat diet on physiology and behavior of borderline hypertensive rats (BHR).

Abstract

The purpose of this study is to determine whether maternal overnutrition contributes to obesity, hypertension, and altered stress reactivity in rats with a genetic predisoposition to mild hypertension. Adult female Wistar rats were maintained on either a high-fat (HF: 60% lard) or low-fat (LF: 10%) diet for approximately 8 weeks, after which they were mated with male spontaneously hypertensive rats (SHR) to yield BHR offspring. Gestating females were maintained on the same diets as prior to impregnation. At parturition, the litters were culled and cross-fostered either to a dam with either low-or high-fat diet, so yielding 4 groups for the period of lactation: HF/HF, LF/LF, HF/LF, LF/HF. At weaning, half the litters were fed Purina chow while the other half were placed on a varied but HF cafeteria diet. These weanling rats were divided among four different experiments: (1) to determine the growth and food intake of the offspring, (2) to determine whether exposure to high salt diet after puberty has differential hypertensive effects as a function of perinatal diet, (3) to determine whether these rats have differential hormonal responses to chronic social stress (resident-intruder protocol), and (4) whether motivation for food is altered (operant protocol). These studies are currently under way and updated results will be presented.