Dietary tyrosine supplementation enhances weight gain in streptozotocin-diabetic rats.
The effect of dietary protein concentration and tyrosine supplementation on growth in streptozotocin (65 mg/kg, ip) diabetic rats was evaluated. When rats were fed diets ranging from 15 to 60% protein, weight gain and feed efficiency were greatest in rats fed the 45% protein diet. Adding tyrosine to this diet (8%, incorporated as a percentage of protein) did not promote further weight gain relative to nonsupplemented diabetic animals. In contrast, rats choosing 45% of total calories as protein by selecting from 10 and 60% protein diets supplemented with either 0, 4, or 8% tyrosine demonstrated a 35% (4% tyrosine) to 45% (8% tyrosine) increase in weight gain. Proximate analysis indicated similar body composition in tyrosine supplemented and nonsupplemented diabetic animals. Including tryptophan (1.45%) with tyrosine in the self-selection diet was without effect. Thus, tyrosine supplementation promoted a modest but consistent and specific increase in weight gained by self-selecting diabetic rats.
D000818:Animals; D001835:Body Weight / Q000187:drug effects*; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D005947:Glucose / Q000378:metabolism; D007328:Insulin / Q000097:blood; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014443:Tyrosine / Q000378:metabolism / Q000494:pharmacology*
D007328:Insulin; D014443:Tyrosine; D005947:Glucose