INSULIN-LIKE GROWTH-FACTOR-I AND ITS BINDING PROTEIN-3 IN SERUM - ARETHEY GOOD SCREENING PROPERTIES FOR THE DIAGNOSIS OF GROWTH-HORMONE DEFICIENCY

Serum insulin-like growth factor-I and insulin-like growth factor bind ing protein-3 are simply-determined screening analytes if growth hormo ne deficiency is suspected. The analysis of growth hormone secretion u sing standardised stimulation tests and secretion profiles is complica ted and expensive in comparison. In retrospect, we have examined the v alue of insulin-like growth factor-I and its binding protein-3 for the diagnostic clarification of patients with short stature (n = 117). In 39/117 patients growth hormone secretion was investigated as ward pat ients. Growth hormone deficiency was diagnosed in 10 patients, for 16 patients the diagnosis was neurosecretory dysfunction. For all patient s (n = 7) with lowered insulin-like growth factor binding protein-3 an d insulin-like growth factor-I values (insulin-like growth factor bind ing protein-3 < 5th percentile, insulin-like growth factor-I < 10th pe rcentile) a growth hormone disorder was proven. Conversely, however, o nly 3/10 patients with classical growth hormone deficiency (n = 3) sho wed a lowering of both analytes. 8/10 patients with classical growth h ormone deficiency and 8/16 patients with neurosecretory dysfunction ha d at least one lowered value. Two patients showed normal values for in sulin-like growth factor-I and insulin-like growth factor binding prot ein-3 despite biochemically proven growth hormone deficiency. The comb ined determination of insulin-like growth factor-I and insulin-like gr owth factor binding protein-3 can provide valuable help during prelimi nary diagnosis of patients of short stature, indicating a disturbance of the growth hormone secretion if the values are lowered. Normal valu es do not, however, exclude the possibility of a growth hormone defici ency. Inpatient endocrinological testing is indispensible if growth ho rmone deficiency is suspected.