THE MAGNITUDE OF GROWTH-HORMONE ELEVATION IS RELATED WITH THE PROPORTION OF MONOMERIC FORM IN ACROMEGALY

In acromegalic patients monomeric GH form constitutes the larger propo rtion of circulating GH; however, no data are available concerning the relation between total GH elevation and the predominance of GH forms. Therefore, we studied the relationship between the degree of GH eleva tion and the proportion of GH isoforms. Sera from 11 patients with act ive acromegaly were subjected to gel chromatography on Sephadex G-100 column and fractions were collected for RIA to measure GH. The monomer ic form of GH was predominant and exhibited a lineal correlation (r = 0.76, p <0.01) with the circulating GH, thus the higher elevation of G H, the major proportion of monomeric GH. IGF-1 changes correlate with changes in monomeric GH but no better than for total GH. There was a c orrelation observed (r = 0.65) between the proportion of low GH forms and the presence of hyperglycemia, although the physiological role of the lower molecular GH forms is still unknown. In conclusion, it was d emonstrated that the relative proportion of GH molecular forms changes according to the magnitude of the elevation of total GH.