Independent effects of food intake and insulin status on insulin-like growth factor-I in young pigs.
The independent effects of decreased food intake and diabetic hyperglycemia on serum GH, serum IGF-I and tissue IGF-I expression were examined in young streptozotocin-diabetic pigs. Each of three treatments (control, diabetic, and insulin-treated diabetic) were represented within three levels of regulated food intake (FI) provided as three meals per day equivalent to 100, 50, and 10% of the voluntary FI consumed by the untreated diabetics. Reduction of food intake was associated with decreased body weight gains, decreased serum IGF-I concentrations, and increased serum GH concentrations. Nutrient restriction also tended to decrease the relative abundance of IGF-I mRNA in liver and skeletal muscle. Diabetic pigs with hyperglycemia and hypoinsulinemia had higher serum concentrations of IGF-I than pair-fed controls, but exogenous insulin treatment of these diabetic pigs increased serum IGF-I even further and also tended to increase the relative abundance of IGF-I mRNA in liver and skeletal muscle. When the statistical effects of reduced FI were eliminated, neither the present form of diabetes nor exogenous insulin affected serum GH. In summary, diabetes-induced changes in IGF-I in these pigs depended primarily on the reduced level of food intake occurring in these hypoinsulinemic, hyperglycemic subjects.
Taylor-Roth
J L
JL
Lilly Research Laboratories, Greenfield, IN 46140, USA.
Malven
P V
PV
Gerrard
D E
DE
Mills
S E
SE
Grant
A L
AL
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000097:blood* / Q000503:physiopathology; D004435:Eating / Q000502:physiology*; D013006:Growth Hormone / Q000097:blood; D007328:Insulin / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D013311:Streptozocin; D013552:Swine; D015430:Weight Gain / Q000502:physiology
D001786:Blood Glucose; D007328:Insulin; D012333:RNA, Messenger; D013311:Streptozocin; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone