Hugues. J N JN; Torresani. T T; Herve. F F; Martin-Pont. B B; Tamboise. A A; Santarelli. J J
In a tiny study of 12 women who had trouble responding to standard IVF hormones, giving the peptide GRF‑1‑29 (a short form of growth‑hormone‑releasing hormone) twice daily boosted their natural growth‑hormone levels and led to a modest rise in the number of follicles and eggs retrieved.
Garcia-Rojas. J F JF; Mangas. A A; Barba. A A; Millan. J J; Dieguez. C C; Zamora. E E
The study shows that giving a synthetic growth‑hormone‑releasing hormone (GHRH‑1‑29) blocks the ability of pentagastrin (a gastrin‑like drug) to raise growth hormone (GH) levels in healthy men. Pentagastrin alone can cause a modest GH spike, but this effect disappears if GHRH has already been administered, suggesting gastrin works upstream in the brain rather than directly on the pituitary.
A lab study on adult female rat pituitary cells found that adding a tiny amount of growth hormone‑releasing factor (GRF‑1‑29) stopped the growth of prolactin‑producing cells (mammotrophs) while letting growth‑hormone‑producing cells (somatotrophs) increase. The effect was seen at extremely low concentrations and didn’t affect other cell types like fibroblasts.
Luo. D S DS; McKeown. B A BA; Rivier. J J; Vale. W W
In a lab test using trout pituitary cells, two fish hormones called carp GRF(1-45) and GRF(1-29) were shown to boost growth hormone release in a dose‑dependent way, while a synthetic hormone called somatostatin-14 reduced it. The study also found that water pressure didn’t change the inhibition, but it did affect the natural hormone release, and that how many cells were in the dish mattered.
de Zegher. F F; Vanderschueren-Lodeweyckx. M M; Spitz. B B; Faijerson. Y Y; Blomberg. F F; Beckers....
Giving the GH‑releasing peptide Sermorelin (GRF‑1‑29) to women right before a C‑section caused only a tiny, not statistically solid, rise in the mother's own growth hormone, didn’t change the placenta’s growth hormone, and didn’t reach the baby at all. In short, the peptide stays with the mother and doesn’t affect the fetus.
In rats, giving growth hormone (GH) changes how the body responds to the hormone‑releasing peptide GRF‑1‑29, and this effect is different between males and females. Female rats keep responding strongly to repeated GRF‑1‑29 shots even while GH is infused, while male rats become less responsive in a regular 3‑hour cycle that gets stretched out by GH. The researchers think this is because GH alters the release of somatostatin (a hormone that blocks GH) differently in the two sexes.
Armstrong. J D JD; Esbenshade. K L KL; Johnson. J L JL; Coffey. M T MT; Heimer. E E; Campbell. R M R...
In a pig study, scientists gave the animals a vaccine that made their bodies produce antibodies against the growth‑hormone‑releasing factor peptide (GRF‑1‑29). The vaccine blocked the normal spikes of growth hormone and lowered IGF‑1 levels, showing that the immune system can neutralize this peptide.
Saermark. T T; Jacobsen. C C; Magee. A A; Vilhardt. H H
The study shows that a synthetic version of growth hormone‑releasing factor (GRF‑1‑29) quickly binds to and is taken into rat pituitary cells, and that this process needs a type of protein modification (fatty‑acid acylation). Blocking this modification with the drug cerulenin stops the hormone from being internalized, but doesn’t affect its breakdown inside the cell.
Gabrielsson. B B; Fairhall. K M KM; Robinson. I C IC
In guinea‑pigs, growth hormone (GH) is released in bursts that can be triggered by a synthetic peptide called GRF‑1‑29. The study shows that giving GRF‑1‑29 in increasing doses makes the animals secrete more GH, and that blocking somatostatin (a GH‑inhibiting hormone) stops the bursts but causes a rebound when the block is lifted.
Dubreuil. P P; Pelletier. G G; Petitclerc. D D; Lapierre. H H; Gaudreau. P P; Brazeau. P P
In growing pigs, blocking somatostatin with a vaccine raised their natural growth hormone (GH) levels and made them respond more consistently to a GH‑releasing peptide (GRF‑1‑29). Fasting also boosted GH, likely by lowering somatostatin and/or increasing GRF signals.
Pastoureau. P P; Charrier. J J; Blanchard. M M MM; Boivin. G G; Dulor. J P JP; Theriez. M M; Barento...
In a study on newborn lambs, giving the peptide GRF‑1‑29 twice daily raised their growth‑hormone (GH) levels, especially in the smaller, low‑birth‑weight animals. The hormone boost lasted longer in those lambs, and a modest rise in IGF‑1 (somatomedin C) was seen at 45 days. However, the treatment didn’t noticeably change bone length growth, only making some growth‑plate cells a bit smaller and increasing cell turnover.
Davis. J R JR; Wilson. E M EM; Vidal. M E ME; Johnson. A P AP; Lynch. S S SS; Sheppard. M C MC
The study looked at how a GH‑releasing peptide (GRF‑1‑29) and other drugs affect growth‑hormone release from human pituitary tumor cells. GRF‑1‑29 raised GH secretion in most of the tumors tested, but the effect on the hormone’s gene activity (mRNA) was weaker and varied a lot. Other compounds like somatostatin and bromocriptine blocked GH release without changing mRNA, and forskolin acted like GRF only in the most responsive tumors.
In young rats, a synthetic peptide that blocks the growth‑hormone‑releasing factor (GRF‑1‑29) stopped the normal spikes of growth hormone and slowed down body, organ, and tail growth without changing how much they ate.
Aitman. T J TJ; Rafferty. B B; Coy. D D; Lynch. S S SS; Clayton. R N RN
In a small study with healthy men, a modified version of the growth‑hormone‑releasing hormone (GHRH) that works great in rats did NOT produce a stronger growth‑hormone spike than the regular human GHRH when given under the skin at a typical dose.
In rats, a synthetic peptide that blocks growth‑hormone‑releasing factor (GRF) can lower the natural bursts of growth hormone (GH) when given into the bloodstream, and it can also stop the GH‑lowering effect of extra GRF when injected into the brain. The peptide doesn’t change prolactin levels, showing it’s specific to GH control.
In rat adrenal gland slices, the peptide VIP caused a strong, dose‑dependent rise in the stress hormones aldosterone and corticosterone, while a related peptide called (N‑Ac‑Tyr1‑D‑Phe2)GRF‑(1‑29)NH2 (the GRF‑1‑29 analog) did not change these hormone levels at all.
The study shows that a short version of the growth‑hormone‑releasing factor peptide (GRF‑1‑29) folds into a stable shape with two helical sections, similar to the longer version, when examined in a lab solution.
Robberecht. P P; Waelbroeck. M M; Coy. D D; De Neef. P P; Camus. J C JC; Christophe. J J
Scientists tested 30 modified versions of the short peptide GRF‑1‑29 to see how changes affect its ability to turn on an enzyme called adenylate cyclase in rat pituitary, liver and pancreas cells. They found that the tail end of the peptide is needed to bind the classic GRF receptor, while the front part of the molecule is crucial for actually activating the enzyme. Some modifications turned the peptide into blockers (antagonists) of either GRF or VIP receptors.
Hümmelink. R R; Rohwedder. R R; Sippell. W G WG
A small study gave nine boys with short stature synthetic growth‑hormone‑releasing factor (GRF‑1‑29) under different dosing schedules. More frequent injections (twice a day) and higher doses led to slightly faster growth of the legs and overall height, but the changes were modest and the study was done in children with growth hormone deficiencies, not healthy adults.
Ross. R J RJ; Rodda. C C; Tsagarakis. S S; Davies. P S PS; Grossman. A A; Rees. L H LH; Preece. M A...
In a small study of 18 kids who lacked growth hormone, twice‑daily injections of a synthetic GHRH peptide helped about half of them grow faster (more than 2 cm per year). A strong GH response before treatment predicted who would benefit, but even kids with weaker responses sometimes grew. Some kids made antibodies against the peptide, yet this didn’t hurt growth.