The role of insulin-like growth factor I in growth of diabetic rats.
Insulin-deficient, streptozotocin-diabetic rats show severe metabolic disturbances and stop growing. Besides insulin, these animals also lack growth hormone and insulin-like growth factor-I. We examined whether or not growth parameters correlate with IGF-I serum levels in young rats with streptozotocin-diabetes of different severity. In the diabetic rats, blood glucose varied between 18.4 and 38.6 mmol/l (healthy controls between 6.1 and 9.3), IGF-I serum levels between 2.6 and 15.6 nmol/l (controls between 19.6 and 26.5), and serum insulin levels between 0.05 and 0.14 nmol/l (controls between 0.36 and 0.55). We found a highly significant linear correlation between IGF-I serum levels and the two investigated growth parameters, tibial epiphyseal width and longitudinal tibial bone growth. The finding that these indices of growth are strongly correlated with IGF-I serum levels in young rats with diabetes of different severity, suggests that IGF-I is a major determinant of growth. This is in keeping with our earlier demonstration that exogenously infused IGF-I promotes growth in diabetic rats.
Binz
K
K
Department of Medicine, University Hospital, Zürich, Switzerland.
Zapf
J
J
Froesch
E R
ER
D000818:Animals; D001846:Bone Development; D003921:Diabetes Mellitus, Experimental / Q000097:blood* / Q000503:physiopathology; D007334:Insulin-Like Growth Factor I / Q000097:blood*; D008297:Male; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D013002:Somatomedins / Q000097:blood*; D013977:Tibia / Q000254:growth & development
D013002:Somatomedins; D007334:Insulin-Like Growth Factor I