Lipogenic cell

The additional pathway diverts glucose 6-phosphate from the first step of glycolysis and reduces NADP" in two redox reactions (Fig. 11-25). This reaction sequence is called the oxidative part of the pathway or the oxidative hexose phosphate shunt. It is especially active in lipogenic cells such as hepatocytes and adipocytes. 

Also, phosphorylation of Akt results in activation of sterol regulatory-element binding protein 1 (SREBP1), a key transcription factor involved in regulation of lipogenic enzymes. In addition, some of the effects of insulin on cell proliferation and survival may be explained by an Akt-dependent inhibition of apoptosis through phosphorylation and inactivation of proa-poptotic proteins (e.g., BAD, Caspase 9). 

Spiegelman BM, Ginty CA (1983) Fibronectin modulation of cell shape and lipogenic gene expression in 3T3-adipocytes. Cell 35(3 Pt 2) 657-666... 

Foretz, M., Pacot, C., Dugail, I., Lemarchand, P., Guichard, C., Le Liepvre, X., Berthelier-Lubrano, C., Spiegelman, B., Kim, J.B., Ferre, P. and Foufelle, F. ADDl/SREBP-lc is required in the activation of hepatic lipogenic gene expression by glucose. Mol Cell Biol, 19 (1999) 3760-3768. 

Increased FASN expression in tumors is an early, common event (Swinnen et al., 2002 Myers et al., 2001) and its correlation with reduced survival and increased recurrence rationalizes the potential for anti-FASN tumor therapeutics (Kuhajda, 2000, 2006 Kridel et al., 2007). As evidence that lipogen-esis as a whole is important in cancer, many of the enzymes upstream of FASN show altered expression patterns in human tumor cells, as well. For instance, ACL is overexpressed in cancer cells of breast and bladder (Szutowicz et al., 1979 Turyn et al., 2003). ACC is overexpressed in breast and prostate cancer cells (Milgraum et al., 1997 Swinnen et al., 2000b, 2006 Heemers et al.,... 

Growth hormone increases the sensitivity of the adipocyte to the lipolytic action of the catecholamines and decreases its sensitivity to the lipogenic action of insulin. These actions lead to the release of free fatty acids and glycerol into the blood to be metabolized by the liver. GH also decreases esterification of fatty acids, thereby reducing triacylglycerol synthesis within the fat cell. Recent evidence suggests that GH may impair glucose uptake by both fat and muscle cells by a postreceptor inhibition of insulin action. 

Fig. 332. Lipogenic pigmentation in a hippocampal pyramidal cell (block 2027) from an unmedicated 369 g old Wistar rat (No. 8). Under pentobarbital anaesthesia (30 mg/kg), the animal was perfus from the abdominal aorta with 2.5% glutaraldehyde in 0.1 M sodium cacodylate buffer (pH 7.4). Postfixation with 1 % osmium tetroxide in sodium cacodylate buffer. Embedded in Epon 812 and sectioned at 50 nm. Lead citrate and uranyl acetate. Film 641-20...

Fig. 340. Lipogenic pigmentation in the follicular cells (block 2144) from a 307 g old Wistar rat (No. 14 breeder S. Ivanovas, Kissleg/Allgau) medicated for 4 months (June 28 to October 20, 1976) with 400 mg piracetam per kg body weight X day...

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