Effects of maternal dietary manipulation during different periods of pregnancy on hepatic glucogenic capacity in fetal and pregnant rats near term

Abstract 

Background and aim: Low birth weight is associated with an increased incidence of adult glucose intolerance, type 2 diabetes and cardiovascular disease in humans. In pregnant rats, dietary calorie or protein deprivation results in growth retarded pups, which become glucose intolerant adults with abnormal hepatic glucose metabolism and gluconeogenic enzyme activities. However, whether these abnormalities are present before birth remain unknown.

Methods and results: This study examined the effects of manipulating dietary protein and carbohydrate intake during rat pregnancy on the fetal and maternal hepatic activities of the gluconeogenic enzymes, glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK). Wistar rats were fed ad libitum with either standard chow throughout pregnancy (25% protein, 57% carbohydrate, n=6) or an isocaloric, low protein, high carbohydrate diet (LPHC, 8% protein, 81% carbohydrate) for different periods of pregnancy (early, 0–10 days, n=6; late, 10–20 days, n=7; throughout, 0–20 days, n=6) before tissue collection at day 20. The LPHC diet had no effect on fetal or placental weights, or on fetal hepatic activities of G6Pase and PEPCK in the early LPHC group. In contrast, fetuses of dams fed the LPHC diet in late or throughout pregnancy had lower body and placental weights, and higher hepatic G6Pase and PEPCK activities than controls. Maternal hepatic G6Pase activity was elevated in all LPHC groups, while maternal PEPCK activity was only increased significantly in the late LPHC group.

Conclusions: Feeding a LPHC diet, particularly during late pregnancy, therefore, up-regulates fetal and maternal hepatic glucogenic capacity.

Keywords: Gluconeogenic enzymes, Dietary manipulation, Hepatic programming, Metabolic programming, Rat