Effects of a chronic GRF treatment on lambs having low or normal birth weight.
Pastoureau. P P; Charrier. J J; Blanchard. M M MM; Boivin. G G; Dulor. J P JP; Theriez. M M; Barenton. B B
Key Findings
- GRF‑1‑29 injections (8 µg/kg twice daily) reliably increased plasma GH in both normal and low‑birth‑weight lambs.
- Low‑birth‑weight lambs showed higher peak GH levels and a longer GH response than normal‑weight lambs.
- Serum IGF‑1 (somatomedin C) rose modestly at day 45 in low‑birth‑weight lambs treated with GRF.
- No significant changes in overall bone length growth were observed; only a reduction in degenerative cell size and a slight increase in growth‑plate cell production were noted.
Practical Outcomes
- For biohackers, the study suggests that GRF‑1‑29 can robustly stimulate GH, but the animal model limits direct translation to humans. The modest IGF‑1 increase and lack of clear bone‑growth benefits mean the data don’t support a new dosing protocol for humans. It mainly reinforces existing ideas that GRF can raise GH, without providing actionable guidance for longevity or performance enhancement.
Summary
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.
Abstract
The effects of a long term treatment with human GRF(1-29)NH2 on plasma growth hormone (GH), somatomedin C (Sm-C), histomorphometric parameters of bone growth and body composition were investigated in normal and low birthweight male lambs. The animals were divided into two groups according to their birthweight: 24 normal birthweight (NBW) lambs weighing more than 4 kg and 22 low birthweight (LBW) lambs weighing less than 2.5 kg at birth. Half of the animals in each group received two daily subcutaneous injections (8 micrograms/kg body weight) of hGRF(1-29) NH2 (GRF) from birth to slaughter at 45 or 90 days of age. The other animals received the solvent only. At the beginning and at the end of the treatment, plasma GH and serum Sm-C concentrations were measured in all groups. After slaughter, a histomorphometric study was performed on undecalcified sections of metacarpal growth plates, and the remaining of the carcass was pulverized to study the chemical body composition. GRF induced GH release in both GRF-treated groups. However, plasma GH reached higher (P less than .001) concentrations and the GRF-induced GH peak lasted longer in LBW than in NBW lambs. At day 45, the GRF treatment increased (P less than .05) serum Sm-C concentrations in LBW. Most of histomorphometric parameters reflecting the metacarpal growth in length, were not statistically modified under GRF treatment. However, the size of degenerative cells was smaller (P less than .05) in LBW treated lambs as compared to controls. Consequently, the cell production in the growth plate was increased (P less than .05) under GRF treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
Study Information
pubmed
1989
10.1016/0739-7240(89)90026-x