ALDH9A1 and obesity due to melanocortin 4 receptor deficiency: Further indication for the PPARα dependency of regulation of the mouse genes encoding OCTN2, ALDH9A1, and BBOX1 is provided by the observation that hepatic mRNA, and protein levels of OCTN2, ALDH9A1, and BBOX1 are decreased in obese mice compared to lean mice [60], because high fat diet-induced obesity was reported to disrupt hepatic PPARα function and to impair PPARα dependent gene transcription [61, 62].