Alaska Pollack Protein Decreases Brain 3-methoxy-4-hydroxyphenylglycol Levels in Fasting Chicks

Alaska pollack protein (APP) reduces serum triacylglycerol and body fat accumulation by the enhancement of basal energy expenditure through fast-twitch muscle hypertrophy in rats. However, the effects of APP on brain function have not yet been clarified. In the present study, we investigated the effects of orally administered APP on the brain levels of 3-methoxy-4-hydroxyphenylglycol (MHPG), which is a metabolite of norepinephrine (NE) and can be used as an index of NE activity, in fasting chicks. Fasting stress significantly decreased plasma glucose, uric acid, triacylglycerol, proline and ornithine while MHPG levels in the brain and plasma corticosterone concentration were not affected. APP dose-dependently decreased MHPG level in the diencephalon, telencephalon and optic lobe. Plasma uric acid, alanine, β-alanine, arginine, anserine, aspartate, asparagine, glycine, histidine, isoleucine, leucine, lysine, 1-methylhistidine, 3-methylhisitidine, ornithine, proline, taurine and valine were dose-dependently increased with the increase of APP. It has been reported that some of them are known to centrally reduce the stress-induced behaviors of chicks. These results suggest that orally administered APP could influence brain NE activity through increase in amino acids to protect against stress conditions.