Submitted on September 12, 2008
Revised on February 11, 2009
Accepted on February 16, 2009
Threonine-deficient diets induced changes in hepatic bioenergetics
Catherine M Ross-Inta1, Yi-Fan Zhang1, Andrew Almendares1, and Cecilia Giulivi2*
1 University of California Davis
2 University of California
* To whom correspondence should be addressed. E-mail: cgiulivi{at}ucdavis.edu.
Diets de
cient in an indispensable amino acid are known to suppress food intake in rats. Few studies were focused at understanding how amino acid deficient diets may elicit biochemical changes at the mitochondrial level. The goal of this study was to evaluate mitochondrial function in rats fed diets with 0.00%, 0.18%, 0.36%, and 0.87% Thr (set at 0 %, 30%, 60% and 140% of Thr requirement for growth). Here, it is described for the first time, that Thr-deficient diets induce a specific uncoupling of mitochondria in liver, especially with NADH-linked substrates, not observed in heart (except for Thr-devoid diet). The advantage of this situation would be to provide more ATP to support growth and maintenance when high-quality protein food (or wealth of high-quality food in general) is available. Conversely, Thr-deficient diets (or deficient-quality protein food) promoted mitochondrial uncoupling in liver. The uncoupling with NADH-substrates would favor the use of nutrients as energy sources with higher FADH-to-NADH ratios, such as fat, minimizing the first irreversible NADH-dependent catabolism of many amino acids, including Thr, thus enhancing the use of the limiting amino acid for protein synthesis when a low quality protein source is available.
