Relationship between serum growth hormone binding protein levels and height in young men

The biochemical mediators responsible for variations in stature among norma l subjects are largely unknown. To obtain some initial information about po tential endocrine factors, we measured the serum concentrations of GH, IGF- 1, IGFBP-3 and GHBP in healthy young men shorter than 159 cm and taller tha n 187 cm, We studied 14 volleyball and basketball players (tall group), and 14 jockey students from a horse racetrack (short group). A careful medical history was taken, including dietary intake, and physical examination with special attention to the possible presence of genetic stigmata was perform ed. Serum prealbumin was determined as an index of nutritional status. A bu ccal smear was performed to exclude Klinefelter's syndrome. The BMI and ser um prealbumin levels were comparable in both groups of individuals. The nut ritional survey, however, revealed that the tall subjects had a higher inta ke of calories (42.2 +/- 11.2 vs 30.1 +/- 15.15 kcal/kg, p<0.05), and prote in (1.5 +/- 0.6 vs 0.8 +/- 0.4 mg/kg, p<0.01). Serum concentrations of GHBP did not differ in the two groups (0.95 +/- 0.37 nmol/l in the tall, and 0. 95 +/- 0.53 nmol/l in the short group), and did not correlate with height, serum IGF-I levels, or BMI, We observed a significant difference in the ser um concentrations of IGF-I in the two groups of individuals (42.02 +/- 9.37 nmol/l in the tall and 31.79 +/- 3.18 nmol/l in the short group, p<0.05), and this growth factor showed a positive correlation with height (r = 0.5, p<0.01). These preliminary findings suggest that final height differences i n young men do not appear to be mediated by variations in GHBP concentratio ns.