Insulin-like growth factors (IGF) I and II and IGF binding proteins 1, 2 and 3 during low-dose growth hormone (GH) infusion and sequential euglycemic and hypoglycemic glucose clamps: studies in GH-deficient patients.
To evaluate the short-term effects of growth hormone (GH), insulin and different levels of glycemia on insulin-like growth factors (IGF) I and II and IGF binding proteins (IGFBP) 1, 2 and 3, we studied six GH-deficient adolescents during a night and the following day in the postabsorptive (basal) state followed by sequential euglycemic (5 mmol/l) and hypoglycemic (3 mmol/l) glucose clamps concomitant with an intravenous infusion (starting at 24.00 h) of GH (35 micrograms/h) or saline. Current GH therapy was withdrawn 24 h prior to each study. Nocturnal levels of IGF-I, IGF-II, IGFBP-2 and IGFBP-3 remained stable during both studies. Nocturnal serum IGFBP-1 increased and correlated inversely with insulin in both studies. Regression analysis revealed a significant inverse correlation between mean nocturnal IGFBP-2 and IGFBP-3 levels. During the daytime, serum IGF-I declined slowly during saline infusion, whereas serum IGF-II remained stable in both studies. Serum IGFBP-1 displayed a gradual significant decline during the basal state and the euglycemic and hypoglycemic clamps seemed to be unaffected by GH levels. By contrast, serum IGFBP-2 remained stable during the same period in both the GH and the saline study. Serum IGFBP-3 declined insignificantly during the daytime in the saline study.(ABSTRACT TRUNCATED AT 250 WORDS)
Jørgensen
J O
JO
Department of Internal Medicine (Diabetes and Endocrinology), Aarhus Kommunehospital, Denmark.
Blum
W F
WF
Horn
N
N
Møller
N
N
Møller
J
J
Ranke
M B
MB
Christiansen
J S
JS
D000328:Adult; D000704:Analysis of Variance; D001786:Blood Glucose / Q000032:analysis; D002352:Carrier Proteins / Q000096:biosynthesis*; D002940:Circadian Rhythm; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D015309:Glucose Clamp Technique; D006130:Growth Disorders / Q000188:drug therapy; D013006:Growth Hormone / Q000172:deficiency / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D007328:Insulin / Q000097:blood; D018970:Insulin-Like Growth Factor Binding Protein 1; D018971:Insulin-Like Growth Factor Binding Protein 2; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis; D007335:Insulin-Like Growth Factor II / Q000096:biosynthesis; D008297:Male; D011897:Random Allocation; D012044:Regression Analysis; D016037:Single-Blind Method; D013002:Somatomedins / Q000096:biosynthesis*
D001786:Blood Glucose; D002352:Carrier Proteins; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D018970:Insulin-Like Growth Factor Binding Protein 1; D018971:Insulin-Like Growth Factor Binding Protein 2; D018969:Insulin-Like Growth Factor Binding Proteins; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D013006:Growth Hormone