Discovery of a new peptide with growth hormone releasing activity

Abstract

The hypothesis that chemical substances secreted by nerve cells in the hypothalamus regulate anterior pituitary functions was first formulated fully by Geoffrey Harris more than thirty years ago. A complete vindication of this view now appears in sight with the recent discovery of a peptide with specific and unusually potent stimulatory effects on growth hormone (GH) secretion. The source of this peptide was not the hypothalamus, as was the case with the discovery of thyrotropin releasing hormone (TRH), gonadotropin releasing hormone (GnRH), corticotropin releasing hormone (CRH) and somatostatin, but rather from pancreatic tumors obtained from two patients 5.10. In both cases, the patient presented clinically with the symptoms and signs of GH excess (acromegaly). In one patient, pituitary enlargement was diagnosed and trans-sphenoidal surgery undertaken; the pituitary was found to show hyperplasia of the GH-secreting cells, the symptoms of acromegaly persisted post-operatively and a pancreatic tumor was subsequently found 15. The second patient had a normal pituitary and two pancreatic tumors 5. In both cases extracts of the pancreatic tumors revealed a peptide of similar structure.