Defective response of plasma growth hormone to growth hormone releasing factor in growth hormone deficient children.
Ko. F Y FY; Chen. W P WP; Lin. C Y CY
Key Findings
- GRF‑1‑29 reliably raises plasma GH, peaking around 45 minutes after an IV dose of 1 µg/kg.
- GH‑deficient children show a significantly smaller GH peak (≈13 ng/mL) compared to normal peers (≈80 ng/mL).
- ~21% of GH‑deficient children had a blunted (half) response, suggesting a hypothalamic origin of their deficiency.
Practical Outcomes
- For biohackers interested in GH‑boosting, GRF‑1‑29 can safely stimulate GH, but the magnitude of increase varies widely, especially in people with underlying GH deficiencies. The test may help differentiate whether low GH is due to pituitary or hypothalamic issues, which could guide whether to use GRF‑1‑29 alone or combine it with other interventions. However, dosing and timing data are limited to children, so extrapolation to healthy adults should be cautious.
Summary
Giving a single dose of the peptide GRF‑1‑29 to kids triggers a spike in their blood growth hormone about 45 minutes later. Normal kids reach high levels, while growth‑hormone‑deficient kids still respond but to a much lower peak. About one‑fifth of the deficient kids barely responded, hinting their problem might lie in the brain rather than the pituitary.
Abstract
In an attempt to establish the reference pattern and the plasma growth hormone (GH) response to growth hormone releasing factor (GRF) (1-29)NH2, 5 normal stature with single kidney children and 14 with idiopathic GH deficient dwarfism received intravenous injections of 1 microgram/kg GRF(1-29)NH2. Plasma GH levels were measured at 0, 15, 30, 45, 60, 90, and 120 min after injection. The results showed that, first, in normal stature with single kidney children, each plasma GH reached peak level (80.31 +/- 19.28 ng/ml) at 45 min after injection. Second, the majority of those with GH deficient dwarfism also obtained maximal GH levels (13.10 +/- 10.78 ng/ml) at 45 min after injection but at significantly lower levels than the normal children (P < 0.01). To compare with that obtained after the insulin-induced hypoglycemia test, the peak GH level after GRF was higher but there was no significant correlation between them. The maximal GH level after GRF(1-29)NH2 injection did not show significant correlation with either chronological age or bone age. Third, 3 of 14 (21.4%) with GH deficient dwarfism had half response to GRF(1-29)NH2. It is reasonable to assume that out of these patients' GH deficiency is of hypothalamic origin. Therefore, GRF test is a safe and useful test for differential diagnosis of defect level in GH deficiency and may become a therapeutic regimen.
Study Information
pubmed
1992