We have recently reported that PPARα deficiency leads to hypoglycaemia and hypoinsulinemia in mice (Yessoufou et al. Endocrinology 147:4410-4418, 2006). Besides, these mice exhibited high adiposity with an inflammatory state. We, therefore, assessed, in this study, the effects of PPARα deficiency on the expression of mRNA encoding for the insulin gene transcription factors in pancreatic β-cells along with those implicated in inflammation in adipose tissues. On fasting, the adult PPARα-null mice were hypoglycemic. Serum insulin concentrations and its pancreatic mRNA transcripts were downregulated in PPARα-null mice, suggesting that PPARα gene deletion contributes to low insulin gene transcription. The PPARα gene deletion downregulates the mRNA expression of insulin gene transcription factors, i.e., Pdx-1, Nkx6.1, and MafA. Besides, the pancreatic function was diminished by PPARα deficiency as PPARα-null mice expressed low pancreatic Glut2 and glucokinase mRNA. PPARα-null mice also expressed high adiponectin and leptin mRNA levels compared to wild type animals. Adipose tissues of PPARα-null mice exhibited upregulation of CD14 and CD68 mRNA, generally expressed by macrophages. PPARα gene deletion downregulates the adipocyte mRNA of certain pro-inflammatory agents, like MCP-1, TNF-α, IL-1β, IL-6, and RANTES, though pro-inflammatory TLR-2 and TLR-4 mRNAs were upregulated in the adipose tissues. Our results suggest that PPARα deficiency, in mice, is implicated in the modulation of insulin gene transcription and inflammatory status in adipose tissues. © Springer Science+Business Media, LLC. 2008.
