This old study shows that the short version of growth‑hormone‑releasing factor (the peptide in sermorelin) works just as well as the longer natural form at raising growth hormone levels, both in healthy people and in patients who lost GH after brain radiation. It also suggests the short peptide can be used to test how much GH the pituitary can release. For DIY health enthusiasts, it confirms that a single 200 µg dose of sermorelin can give a measurable GH spike, but the data are from a tiny group and not a new breakthrough.

Human pancreatic growth hormone releasing factor (hpGHRF(1-40] stimulates the release of growth hormone in normal subjects and some patients with growth hormone deficiency. A study comparing the shorter chain amidated analogue hpGHRF(1-29) with an equivalent dose of hpGHRF(1-40) in seven normal subjects showed no significant difference in growth hormone response between the two preparations. Six patients with prolactinomas were also tested; these patients had received megavoltage radiotherapy previously but had developed growth hormone deficiency as shown by insulin induced hypoglycaemia. In all six patients 200 micrograms hpGHRF(1-40) or hpGHRF(1-29)NH2 produced an increase in the serum growth hormone concentration. These data suggest that hpGHRF(1-29)NH2 may be useful for testing the readily releasable pool of growth hormone in the pituitary and that cases of hypothalamo-pituitary irradiation resulting in growth hormone deficiency may be due to failure of synthesis or delivery of endogenous GHRF from the hypothalamus to pituitary cells.