GHRH

What was characterized

In 1982 Rivier, Spiess, Thorner, and Vale published the characterization of a growth hormone-releasing factor from a human pancreatic islet tumour. [1] PMID: 6292724 That paper is the citation for the molecule as an isolatable peptide with a name, not a vibe. Hypothalamic GHRH is the physiological signal. The tumour peptide is how the sequence became chemistry. This entry does not reprint a sequence or a dose. The compound pages for sermorelin Sermorelin growth hormone-releasing hormone (GHRH) analog GHRH analog for endogenous growth hormone stimulation and tesamorelin Tesamorelin growth hormone-releasing hormone (GHRH) analog GHRH analogue studied for visceral fat reduction and GH-axis stimulation are where analogues of this family are discussed as specific molecules.

Kojima's ghrelin paper, seventeen years later, is the citation that keeps the map honest. The authors write that growth-hormone secretagogues act through their own receptor, and that this is a mechanism for regulating growth-hormone release distinct from hypothalamic GHRH. They conclude that release from the pituitary may be regulated not only by GHRH but also by ghrelin. [2] PMID: 10604470

Why the abbreviation gets misused

"GHRH" and "GHRP" differ by one letter and describe different receptors. GHRP-type peptides were built as secretagogues. Bowers' 1984 hexapeptide released growth hormone without, in those experiments, a concomitant release of several other pituitary hormones. [3] PMID: 6714155 That is a secretagogue result. It does not make the hexapeptide GHRH.

Guides that say "GH peptide" and then list sermorelin Sermorelin growth hormone-releasing hormone (GHRH) analog GHRH analog for endogenous growth hormone stimulation next to ipamorelin Ipamorelin growth hormone secretagogue (GHS) / selective ghrelin receptor agonist Selective growth hormone secretagogue are listing two families. Sermorelin is discussed on this site as a GHRH analogue. Ipamorelin is discussed on the secretagogue side. The glossary does not merge those pages. It gives the abbreviation a URL so the guides can link the word instead of defining it in a parenthesis every time.

What GHRH is not

It is not measured by a half-life copied from a different peptide. It is not reconstituted by a special rule. It is not evidence that a research vial labeled "GHRH fragment" contains the hypothalamic hormone, an analogue, or anything at all. Identity is an analytical question. The abbreviation only tells you which biological conversation the seller is claiming to join.

It is also not an instruction to combine a GHRH analogue with a secretagogue. Stack pages can discuss that design. This page stops at the definition: a hypothalamic releasing hormone, distinct from both growth hormone and the ghrelin receptor pathway.

Pages that already depend on the distinction

The GHRH-versus-GHRP guide, the secretagogues guide, and the growth-hormone peptides guide are the long reads. If those pages and this definition ever disagree, the primary papers win, and the page that overreached should be edited. A glossary entry is not a higher authority than Rivier or Kojima. It is a stable place to point.