The interaction of growth hormone, somatomedin and oestrogen in patients with Turner's syndrome

Baseline somatomedin activity in seven of eight patients with Turner's syndrome was found to be within normal limits. Somatomedin activity readily suppressed with estrogen administration. The overall mean serum somatomedin activity during estrogen therapy (0.87 U/ml, SD 0.15) was significantly lower (P<0.005) than the mean of the control serum somatomedin activities (1.09 U/ml, SD 0.24). During estrogen therapy, suggestive elevations of fasting growth hormone levels were noted in five of eight patients. The data indicate that estrogenic suppression of serum somatomedin was not due to decreased growth hormone secretion and suggest the existence of a negative feedback link between somatomedin and growth hormone.