Dose response of two synthetic human growth hormone-releasing factors on growth hormone release in heifers and pigs.
Peticlerc. D D; Pelletier. G G; Lapierre. H H; Gaudreau. P P; Couture. Y Y; Dubreuil. P P; Morisset. J J; Brazeau. P P
Key Findings
- Both hGRF (1‑44)NH2 and hGRF (1‑29)NH2 equally stimulate GH release in dairy heifers and pigs across all tested doses
- Peak GH concentrations and area‑under‑the‑curve values did not differ significantly between the two peptides
- At the highest dose, cows showed a biphasic GH release and pigs showed more variable responses
Practical Outcomes
- For biohackers, the study supports using the shorter sermorelin (1‑29) peptide, as it appears just as potent as the longer form for triggering GH. The dose‑response data suggest a range of effective doses, but because the work was done in animals, human dosing should still follow established clinical guidelines and be approached cautiously.
Summary
In this animal study, two versions of a human growth‑hormone‑releasing peptide—one short (1‑29, like sermorelin) and one longer (1‑44)—were given to young cows and pigs at several doses. Both peptides caused the same amount of growth‑hormone release, with no significant differences in peak levels or overall exposure, although the highest dose gave a two‑phase spike in cows and the pig response was more erratic. The results suggest the shorter peptide works just as well as the longer one for boosting GH, but the findings are from livestock, not people.
Abstract
This study was undertaken to evaluate the biological potency of two synthetic human growth hormone-releasing factors, hGRF (1-44)NH2 and hGRF (1-29)NH2, on growth hormone (GH) release in young dairy heifers (n = 10) and pigs (n = 10). In each species, the GH response to an iv injection (0, .067, .2, .6 and 1.8 nmol.kg-1 body weight) of each peptide was evaluated in a double 5 X 5 Latin square design. In each square, there were five animals injected with either hGRF (1-44)NH2 or hGRF (1-29)NH2. Main effects were doses (n = 5) of hGRF and days (n = 5) of injection. In both species, data indicated that hGRF (1-44)NH2 and hGRF (1-29)NH2 equally stimulate GH secretion at all doses. In dairy heifers, average peak concentrations (81.7, 94.7, 84.5 and 93.7 ng.ml-1 vs 91.5, 81.0, 94.3 and 91.6 ng.ml-1) and area under the GH response curve (3,661, 4,541, 7,196 and 6,788 ng.ml-1.min vs 3,000, 3,982, 5,639 and 6,724 ng.ml-1.min) were not different (P greater than .05) between hGRF(1-44)NH2 and hGRF(1-29)NH2 at .067, .2, .6 and 1.8 nmol.kg-1, respectively. Similarly, in pigs, average peak concentrations (35.6, 38.6, 76.5 and 73.8 ng.ml-1 vs 28.7, 30.0, 41.3 and 80.8 ng.ml-1) and area under the GH curve (1,576, 1,567, 3,299 and 3,622 ng.ml-1.min vs 1,115, 1,658, 1,482 and 2,528 ng.ml-1.min) were not different (P greater than .05) between both peptides. A biphasic release of GH after hGRF (1-44)NH2 and hGRH (1-29)NH2 injection was observed at the highest dose in heifers. The GH response to hGRF injection was much more variable in pigs as compared with dairy heifers. In conclusion, hGRF (1-44)NH2 and its (1-29)NH2 fragment are equipotent in stimulating GH release in dairy heifers and pigs.
Study Information
pubmed
1987
10.2527/jas1987.654996x