Effects of Taurine Supplementation Upon Food Intake and Central Insulin Signaling in Malnourished Mice Fed on a High-Fat Diet - Advances in Experimental Medicine and Biology - page 90

increased calorie intake. TAU promoted increased hypothalamic insulin action only
in CH mice which was linked to prevention of overfeeding, obesity, and glucose
intolerance. Protein-restriction promoted metabolic damages that were not prevented
by TAU supplementation.

Abbreviations

TAU Taurine

ARC Arcuate nuclei

T2DM Type 2 diabetes mellitus

CNS Central nervous system

ICV Intracerebroventricular

TNF Tumor necrosis factor

10.1 Introduction

The hypothalamic Arcuate nuclei (ARC) control feeding behavior and sympathetic/
parasympathetic tones modulating body metabolism (Plum et al. 2006 ; Schwartz et al.
2000 ). Insulin crosses the blood-brain barrier and binds to its receptor (IR) located in
the ARC. IR activated phosphorylates itself and its substrates (IRS) and leads to phos-
phatidylinositol-3 kinase (PI3K) activation and increased Akt phosphorylation (pAkt)
(Tsai et al. 2003). Central activation of this pathway inhibits the synthesis of orexi-
genic neuropeptides, such as the neuropeptide Y (NPY) and the agouti peptide (AgRP),
and stimulates the secretion of anorexigenic neuropeptides, proopiomelanocortin
(POMC), and the cocaine-and-amphetamine-regulated transcript (CART) (Morton
et al. 2006 ; Badman and Flier, 2005 ). Therefore, the hypothalamic activation of insu-
lin signaling regulates food intake in order to maintain an adequate body weight.
Obesity is a factor linked to peripheral and central insulin resistance leading to
type 2 diabetes (T2DM) (Kahn et al. 2006 ). Impaired central action of insulin in the
obesity results in a vicious circle which provides an increase in weight gain
(Schwartz and Porte 2005 ) .
Protein-malnutrition during gestation is a frequent cause of low birth weight, and
is associated with increased susceptibility for developing chronic diseases (Barker
et al. 1993 ). Previous reports showed no alteration in IRS1/2 and Akt protein con-
tent in the cerebral cortex from calorie-restricted rats (Mollinedo et al. 2010 ) .
Disrupted insulin signaling in the central nervous system (CNS) reflects on food
intake and may link malnutrition in early life and development of T2DM in adult-
hood (Orozco-Solís et al. 2010 ) .
Taurine (TAU) is a sulfur-containing amino acid present in high concentration in
newborn mice brain. This amino acid is responsible for the maintenance of intracel-
lular osmotic balance (L'Amoreaux et al. 2010 ). TAU treatment during mice develop-
ment causes increase of size and number of pancreatic islets without altering exocrine