Studies in constitutionally tall adolescents: somatostatin decrease associated with growth hormone increase after TRH injection.

The paradoxical GH response to TRH observed in certain adolescents with constitutional tall stature is associated with a 60% fall in plasma levels of somatostatin. Conversely, those tall subjects who do not show a GH increase after TRH, or during a saline control infusion maintain steady levels of somatostatin in plasma. It is thus hypothesized that the GH release after TRH is due to a decreased inhibitory effect of somatostatin at the pituitary level and that this reduced effect may play an aetiological role in certain children with 'constitutional' tall stature.