Cranial irradiation for cerebral and nasopharyngeal tumours in children: evidence for the production of a hypothalamic defect in growth hormone release.
Blacklay. A A; Grossman. A A; Ross. R J RJ; Savage. M O MO; Davies. P S PS; Plowman. P N PN; Coy. D H DH; Besser. G M GM
Key Findings
- All nine irradiated children showed a rise in GH after receiving synthetic GHRH (1-29).
- Five children had a strong response, with peak GH levels >20 µg/L.
- The results imply that hypothalamic damage, not pituitary failure, causes the GH deficiency in these cases.
Practical Outcomes
- For biohackers interested in sermorelin, the data confirm that the peptide can effectively stimulate GH when the pituitary is functional but the brain's natural GHRH signal is missing. This supports using sermorelin as an alternative to direct GH injections in specific deficiency scenarios, though the study focuses on children with radiation damage, so extrapolation to healthy adults should be cautious.
Summary
The study shows that a synthetic version of the hormone that tells the pituitary to release growth hormone (GHRH, also known as sermorelin) can still trigger growth hormone spikes in kids whose brains were irradiated and who have growth hormone deficiency. This suggests the problem is a lack of the brain's signal, not a broken pituitary, and that giving the synthetic signal can work as a treatment.
Abstract
A synthetic 29-amino acid analogue of human pancreatic GH-releasing hormone (GHRH(1-29)NH2) has recently been shown to stimulate the release of GH in normal subjects. We have studied the GH response to GHRH(1-29)NH2 in nine children irradiated for brain and nasopharyngeal tumours, who were not growing and were deficient in GH as assessed by insulin-induced hypoglycaemia. Serum GH rose in response to GHRH(1-29)NH2 in all the children, and in five the peak serum GH response was greater than 20 mu./l. The data suggest that when hypothalamo-pituitary irradiation results in GH deficiency, this is due to a failure of the synthesis or delivery of endogenous GHRH from the hypothalamus to the pituitary cells. It also suggests that it may be possible to treat such children using synthetic GHRH in place of exogenous GH.
Study Information
pubmed
1986
10.1677/joe.0.1080025