Growth Hormone
Investigational
GHRP-6
Also known as: Growth Hormone Releasing Peptide 6, GHRP6, His-D-Trp-Ala-Trp-D-Phe-Lys-NH2, SKF-110679
Synthetic hexapeptide GHRP, an older-generation ghrelin-receptor agonist. Studied in growth-hormone-axis research.
Research overview
GHRP-6 (growth hormone releasing peptide 6, also coded SK&F 110679) is a synthetic six-amino-acid peptide, His-D-Trp-Ala-Trp-D-Phe-Lys-NH2. Cyril Bowers and colleagues described it in 1984, more than ten years before its target was found. In rat pituitary cells, and in rats, monkeys, lambs and calves, it caused a rapid, short-lived rise in growth hormone (Bowers et al., Endocrinology 1984). Its receptor, the growth hormone secretagogue receptor, was identified in 1996, and ghrelin, the body's own hormone for that receptor, was found in 1999.
Studies in people have been short laboratory studies that measured hormone levels for a few hours. Early work in healthy volunteers found that GHRP-6 and growth hormone releasing hormone (GHRH) together gave a larger growth hormone response than either alone (Thorner et al., 1990). There are no long-term controlled trials in people, GHRP-6 has never been licensed as a medicine, and its effects over months and its long-term safety are unknown. Supplied for laboratory research use only.
Mechanism of action
GHRP-6 binds the growth hormone secretagogue receptor (GHS-R1a), the same receptor that the hormone ghrelin acts on. This receptor is found on growth hormone producing cells in the pituitary and on nerve cells in the hypothalamus. Binding triggers a short burst of growth hormone release. Early studies suggested it acts at both the hypothalamus and the pituitary, and that its effect adds to that of GHRH.