The effects of diet and duration of diabetes on hypermethioninemia in streptozotocin-diabetic rats.
There are conflicting reports concerning the existence of severe hypermethioninemia in rats made diabetic with the pancreotoxin, streptozotocin. To determine whether this discrepancy is due to experimental differences in the severity of diabetes or the diet fed to the animals, streptozotocin-diabetic and control rats were fed either a casein-based semipurified diet or laboratory chow for 2 or 5 weeks. Plasma methionine concentrations were elevated six- to nine-fold after 2 weeks in the casein-fed diabetics compared with both their own controls and the chow-fed diabetics, respectively. Circulating methionine levels had declined sharply by 5 weeks in the casein-fed diabetics but were still more than twice those of the casein-fed control and chow-fed diabetic levels. Since methionine intakes were only 30% greater in the casein-fed diabetics than in the chow-fed diabetics, it is unlikely that this is the sole cause of the large differences in plasma methionine levels. The reason for the difference in circulating Met levels could not be explained on the basis of overall amino acid availability, since growth, nitrogen balance, and plasma large neutral amino acid profiles (excluding Met) were similar within control and diabetic groups fed the two diets.
Dyer
J R
JR
Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Ont., Canada.
Greenwood
C E
CE
McBurney
M I
MI
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000097:blood*; D004032:Diet; D005243:Feces / Q000032:analysis; D008297:Male; D008715:Methionine / Q000097:blood*; D009584:Nitrogen / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D000596:Amino Acids; D001786:Blood Glucose; D008715:Methionine; D009584:Nitrogen