Hexarelin and GHRH stimulated GH production from porcine and human lymphocytes, demonstrating that immune cells have a local GH system that can be activated by GH secretagogues.
Immune cells make GHLymphocytes produced GH directly in response to hexarelin — GH secretagogues can enhance immune function through a local, pituitary-independent mechanism
What the researchers found
Hexarelin and GHRH stimulated GH production directly from porcine and human lymphocytes, demonstrating functional GHS-R and GHRH-R on immune cells with a local GH autocrine/paracrine system.
Why it matters
A local GH system in immune cells means GH secretagogues could directly boost immune function — not just indirectly through pituitary GH release. This direct immune effect adds therapeutic value.
How the study worked
In-vitro study using cultured porcine and human lymphocytes. Hexarelin and GHRH stimulation with GH measurement in culture supernatant by RIA. Receptor expression confirmed.
What this study cannot tell us
In-vitro lymphocyte culture. The amount of GH produced locally may be small relative to pituitary output. Physiological significance uncertain.
How to read the evidence
Preliminary in-vitro evidence from both porcine and human lymphocytes demonstrating direct GH production from immune cells.
When this study was published
Published in 2002. Local GH production by immune cells has been further characterized and is recognized as part of the immune-endocrine network.
The bigger picture
The immune system produces many of the same hormones as the endocrine system, creating local signaling networks. This lymphocyte GH system adds immune function support to GH secretagogues' therapeutic profile.
Questions still open
- Does local lymphocyte GH contribute to immune function maintenance?
- Could GH secretagogues enhance immunity through this local mechanism?
- Is immune cell GH production impaired in immunodeficiency?
Common questions
Can immune cells make growth hormone?
Why does this matter?
Read the original research
Growth hormone secretagogue (GHS) analogue, hexarelin stimulates GH from peripheral lymphocytes.
Experimental and clinical endocrinology & diabetes : official journal, German Society of Endocrinology [and] German Diabetes Association, 110(7), 343-7
Citation
Poppi, L; Dixit, V D; Baratta, M; Giustina, A; Tamanini, C; Parvizi, N. (2002). Growth hormone secretagogue (GHS) analogue, hexarelin stimulates GH from peripheral lymphocytes.. Experimental and clinical endocrinology & diabetes : official journal, German Society of Endocrinology [and] German Diabetes Association, 110(7), 343-7.