The present study examines how tyrosine (TYR) levels and catecholamine synthesis and Trp levels and serotonin synthesis change when different proteins are chronically ingested in the same range of dietary protein contents. For 8 days male rats ingested diets containing 2-10% protein (zein, gluten, casein, soy protein, alpha-lactalbumin). The last day they were sacrificed and brain samples were used for amino acid analysis including 5-hydroxytryptophan (an index of serotonin synthesis rate). Trp levels and serotonin synthesis rate varied significantly with the protein ingested. The effect of dietary protein on brain Trp was highly correlated with its effect on serotonin synthesis. It was seen that the Trp/LNAA ratio was higher with ALAC intake and higher cortical Trp concentration positively correlated with more 5-hydroxytryptophan.
Year: 2011
Nationality: USA
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