Growth hormone responses to GH‐releasing peptide (GHRP‐6) in hypothyroidism

Abstract

We have shown that patients with primary hypothyroidism have higher GH responses to GHRP-6 than to GHRH, which are markedly blunted. When GHRP-6 was associated with GHRH, a significant increase in the GH response was observed in these patients, which could suggest a role for somatostatin in this process. Our data suggest that thyroid hormones modulate GH release induced by GHRH and GHRP-6 through different mechanisms. However, additional studies are necessary to further elucidate this hypothesis.

Iopanoic acid‐induced decrease of circulating T3 causes a significant increase in GH responsiveness to GH releasing hormone in thyrotoxic patients

“…It has previously been suggested that thyroid hormones could modulate intracellular mechanisms in the somatotroph ( Ramos‐Dias et al ., 1996 ; Pimentel‐Filho et al ., 1997 ). It has recently been demonstrated that hyperthyroid patients have a normal GH response to GHRP‐6 associated with a blunted GH response to GHRH ( Ramos‐Dias et al ., 1996 ).…”