Radioimmunoassay for insulin-like growth factor II (IGF-II).
Insulin-like growth factor II (IGF-II) levels in human plasma were measured in physiological and pathological conditions by radioimmunoassay (RIA) with biosynthetic IGF-II. This RIA was specific for IGF-II and cross-reactivity with IGF-I was 1%. The sensitivity was 15 pg/tube with 50% displacement at 50 pg/tube. The intra- and inter-assay coefficients of variation for IGF-II were 6.3 and 9.3%, respectively. The plasma IGF-II levels in normal adults, patients with hypopituitarism and patients with active acromegaly were 589.6 +/- 15.8, 800.9 +/- 45.6 and 330.3 +/- 24.3 ng/ml, respectively. After human growth hormone (hGH) treatment in hypopituitarism, IGF-II slightly increased, but not significantly. After adenomectomy in patients with acromegaly, IGF-II significantly decreased. These data indicate that IGF-II concentrations in plasma were partially GH dependent. This GH dependency was less than that of IGF-I. IGF-II was low in patients with anorexia nervosa and with liver cirrhosis and high in patients with renal failure. In two cases with extrapancreatic tumor-associated hypoglycemia, plasma IGF-II was increased to 1123.8 and 843.5 ng/ml, and returned to normal after tumor resection. These data showed that IGF-II was partly dependent on GH and nutritional conditions and that IGF-II was the most likely cause of some cases of hypoglycemia with extrapancreatic tumor. This specific and sensitive RIA of IGF-II would be useful in evaluating its physiological and pathological role in plasma and tissue.
Asakawa
K
K
Department of Internal Medicine, Tokyo Women's Medical College, Japan.
Hizuka
N
N
Takano
K
K
Fukuda
I
I
Sukegawa
I
I
Demura
H
H
Shizume
K
K
D000172:Acromegaly / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000818:Animals; D000856:Anorexia Nervosa / Q000378:metabolism; D002417:Cattle; D002648:Child; D002675:Child, Preschool; D003920:Diabetes Mellitus / Q000378:metabolism; D005260:Female; D006801:Humans; D007003:Hypoglycemia / Q000378:metabolism; D007018:Hypopituitarism / Q000378:metabolism; D007223:Infant; D007328:Insulin / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000378:metabolism*; D007674:Kidney Diseases / Q000378:metabolism; D008103:Liver Cirrhosis / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011247:Pregnancy / Q000378:metabolism; D011863:Radioimmunoassay / Q000379:methods*; D014424:Turner Syndrome / Q000378:metabolism
D007328:Insulin; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II