Interaction of carp growth hormone-releasing factor and somatostatin on in vitro release of growth hormone in rainbow trout (Oncorhynchus mykiss).
Luo. D D; McKeown. B A BA
Key Findings
- Somatostatin (SS) significantly reduces GH secretion that is normally triggered by carp GRF‑1‑29.
- The antagonism between SS and GRF‑1‑29 is non‑competitive, indicating a distinct interaction at the pituitary level.
- Even high concentrations of GRF‑1‑29 cannot reverse the inhibitory effect of somatostatin once it has bound to the cells.
Practical Outcomes
- For human biohackers, the study offers limited direct guidance because it was done in fish cells. However, it suggests that somatostatin‑like compounds could blunt the GH‑boosting effects of GHRH analogs such as GRF‑1‑29, so timing or avoiding somatostatin activity might be important when trying to raise GH levels.
Summary
In a lab study using rainbow trout pituitary cells, the researchers found that the hormone somatostatin blocks the ability of a growth‑hormone‑releasing factor (GRF‑1‑29) to stimulate growth hormone release. This blocking effect is non‑competitive, meaning somatostatin interferes with the GRF signal in a way that can't be easily overcome by simply adding more GRF.
Abstract
Possible antagonism between somatostatin (SS) and carp growth hormone-releasing factor (GRF) on growth hormone (GH) secretion was examined by radioimmunoassay in a dispersed rainbow trout pituitary cell culture system. SS (3 nM) significantly antagonized carp GRF(1-29; 1 nM, 10 nM)-induced GH secretion. The slope of the dose-response curve for carp GRF(1-29) with SS was statistically different from that of carp GRF(1-29) alone (p less than 0.05) suggesting a noncompetitive antagonism of SS to carp GRF. The carp GRF(1-29) was also indicated to be a noncompetitive antagonist to SS (p = 0.056). Carp GRF(1-29; 100 nM) was unable to restore the inhibitory effect of SS on GH release after pre-exposure of SS (30 nM) to the pituitary cells. We conclude that SS antagonizes carp GRF on GH release at the pituitary level in rainbow trout and this antagonism is noncompetitive. SS has a postantagonism to carp GRF which may implicate some important physiological adaptations in teleosts.
Study Information
pubmed
1991
1991-10-01T00:00:00.000Z
10.1159/000125914
24