Differential hepatic lobar gene expression in offspring exposed to altered maternal dietary protein intake

Abstract

Increased plasma fibrinogen concentrations are a recognized risk factor for coronary heart disease, and increased fibrinogen levels in adults are associated with parameters of reduced early growth. We studied fibrinogen gene expression in adult offspring of dams fed either a 20% (control) or an 8% protein diet [maternal low-protein (MLP) rats] during pregnancy and lactation and determined whether any effects were consistent between left and right liver lobes, since the fetal liver has a unique blood supply that produces differential stimuli to the left and right lobes. In MLP offspring, there was a reduction in all three fibrinogen mRNA copy numbers in the left liver lobe [left vs. right lobes for α-, β-, and γ-fibrinogen (×106 copies/ng total RNA): 8.04 vs. 23.16, P < 0.001; 4.74 vs. 13.07, P< 0.001; and 4.61 vs. 16.38, P = 0.007, respectively], with a parallel reduction in fibrinogen concentration in the left liver lobe (8.53 ± 0.33 vs. 10.41 ± 0.65 arbitrary units, P = 0.014, left and right lobes, respectively). No such effect was observed in offspring of control dams. To investigate the underlying mechanism, glucocorticoid receptor function and mRNA levels were studied, since expression of fibrinogen genes is regulated by glucocorticoid hormones. The binding affinity of the high-affinity glucocorticoid receptor was reduced only in the left liver lobe of the MLP offspring ( P = 0.02, left. vs. right), with a parallel reduction in this lobe in glucocorticoid receptor mRNA level ( P = 0.006, left vs. right). In conclusion, maternal dietary protein restriction reduces fibrinogen gene expression, fibrinogen protein, and mRNA level and binding affinity of glucocorticoid receptors only in the left liver lobe of the adult offspring.