Adipose tissue alanine

Hormones can modify the concentration of precursors, particularly the lipolytic hormones (growth hormone, glucagon, adrenaline) and cortisol. The lipolytic hormones stimulate lipolysis in adipose tissue so that they increase glycerol release and the glycerol is then available for gluconeogenesis. Cortisol increases protein degradation in muscle, which increases the release of amino acids (especially glutamine and alanine) from muscle (Chapter 18). 

The main precursors of gluconeogenesis in the liver are lactate from anaerobically working muscle cells and from erythrocytes, glucogenic amino acids from the digestive tract and muscles (mainly alanine), and glycerol from adipose tissue. The kidney mainly uses amino acids for gluconeogenesis (Glu, Gin see p.328). 

The kidney brush border also possesses a carnosine transport system and there is evidence that kidney also contains an active carnosinase (Sauerhoefer et al., 2005). There is also evidence that carnosine can influence sympathetic nervous activity in kidney (Tanida et al., 2005) as well as brown (Tanida et al., 2007) and white adipose tissue (Shen et al., 2008). Other studies have shown that carnosine has antidepressant activity in rats (Tomonaga et al., 2008). In chicks, carnosine induces hyperactivity (Tsuneyoshi et al., 2007) whereas its reverse structure (L-histidinyl-13-alanine) has sedative and hypnotic effects (Tsuneyoshi et al., 2008). The mechanisms involved in remain obscure however. 

Yeon, B., Park, M.H., Moon, H.J., Kim, S.J., Cheon, Y.W., Jeong, B. 3D culture of adipose-tissue-derived stem cells mainly leads to chondrogenesis in poly(ethylene glycol)-poly0-alanine) diblock copolymer thermogel. Biomacromolecules 14,3256-3266 (2013)... 

The three major carbon sources for gluconeogenesis in humans are lactate, glycerol, and amino acids, particularly alanine. Lactate is produced by anaerobic glycolysis in tissues such as exercising muscle or red blood cells, as well as by adipocytes during the fed state. Glycerol is released from adipose stores of... 

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