Consumption of carotenoid-rich (Gac) aril improves glycemic control in type 2 diabetic mice partially through taste receptor type 1 mediated glucagon-like peptide 1 secretion.

Incretin-based therapies are widely used to improve glycemic control and β cell dysfunction in the treatment of type 2 diabetes. (Gac fruit), a nutritious melon cultivated in many regions, has underexplored health benefits, particular its edible aril. This study comprehensively investigates the stimulatory effect of Gac aril on glucagon-like peptide 1 (GLP-1) secretion, identifies the responsible active constituents, and explores the underlying mechanisms related to its anti-diabetic effects.

Regulation of steroid production: analysis of Cyp11a1 promoter.

CYP11A1 is a key enzyme in steroid synthesis abundantly expressed in the adrenal, testis, ovary, and placenta. This article reviews recent studies on cis-regulatory elements and trans-regulators of the CYP11A1 promoter, with special focus on their tissue-specific regulation. Trans-regulators include tissue-specific factors such as SF-1, DAX-1, TReP-132, LBP, and GATA that regulate tissue-specific expression of CYP11A1.

Mutation of mouse Cyp11a1 promoter caused tissue-specific reduction of gene expression and blunted stress response without affecting reproduction.

Steroids are synthesized mainly from the adrenal glands catalyzed by steroidogenic enzymes; the expression of these enzymes is controlled by transcription factor steroidogenic factor-1 (SF-1; NR5A1). To understand the physiological effect of genetic changes on steroid secretion, we used Cre-LoxP and gene targeting technology to mutate the binding sequence for SF-1 (SF-1 response element) on the promoter of the mouse Cyp11a1 gene, which encodes a critical enzyme for steroid biosynthesis. The resulting Cyp11a1 L/L mice expressed about 7-fold less cytochrome P450 side-chain cleavage enzyme (CYP11A1) in the adrenal and testis but expressed normal amounts of CYP11A1 in the placenta and ovary.

Transcriptional regulation of human CYP11A1 in gonads and adrenals.

The CYP11A1 gene encodes the cholesterol side-chain cleavage enzyme, also termed cytochrome P450scc, which catalyzes the conversion of cholesterol to pregnenolone in the first step of steroid biosynthesis in mitochondria. The adrenal- and gonad-selective, hormonally and developmentally regulated expression of CYP11A1 is principally driven by its 2.3 kb promoter.

Superoxide dismutase and catalase inhibit oxidized low-density lipoprotein-induced human aortic smooth muscle cell proliferation: role of cell-cycle regulation, mitogen-activated protein kinases, and transcription factors.

Several antioxidant enzymes, including copper, zinc-superoxide dismutase (Cu, Zn-SOD) and catalase, have been suggested to be protective against the proliferation of vascular smooth muscle cells exposed to oxidative stress. In the present study, we investigated effects of Cu, Zn-SOD and/or catalase on oxLDL-induced proliferation of, and intracellular signaling in, human aortic smooth muscle cells (HASMCs). HASMCs were transfected with adenovirus carrying the human Cu, Zn-SOD gene and/or the human catalase gene.