Effects of prenatal alcohol on γ-glutamyl transpeptidase in various brain regions

Abstract Prenatal exposure of rats to alcohol produces morphological, biochemical, behavioral and physiological abnormalities. The enzyme γ-glutamyl transpeptidase activity is increased when an animal is exposed to alcohol chronically. We examined the effect of the in utero exposure to alcohol on the regional brain distribution of γ-GTP. Pregnant rats were placed into the following treatment groups: LC (ad lib lab chow and water), PF (pair-fed), 10% EDC (ethanol derived calories), 20% EDC and 35% EDC. The LC group was fed lab chow and water ad lib, the PF, 10% EDC, 20% EDC and 35% EDC groups were fed a liquid diet containing either 0%, 2%, 4% or 6.7% v/v ethanol, respectively. All the treatment groups received the same volume of an isocaloric diet as was consumed by the 35% EDC group. At birth, litters were culled to six and cross fostered to untreated surrogate mothers. Pups were sacrificed at 30 days of age and brains dissected into 8 regions. Each brain region was homogenized and divided into soluble and membrane bound fractions by centrifugation and digestion with deoxycholic acid. γ-GTP activity was then measured. It was determined that the in utero exposure to alcohol produces an increase in brain γ-GTP activity. The increase in γ-GTP activity in some areas of brain is maintained at least until the animals are 30 days old. Alcohol treatment had no effect on the activity associated with the soluble form of enzyme. However, the activity associated with the membrane bound form of the enzyme was increased in several brain regions. In the midbrain and hypothalamus the activity was increased in a dose-dependent manner. These animals may thus be better able to degrade and take up higher amounts of amino acids for glutathione synthesis.