The human fetal pituitary expresses functional GHRP receptors by mid-gestation, and GHRP-2 stimulated GH release from fetal pituitary cells, showing the GH secretagogue system is active before birth.
Active before birthFunctional GHRP receptors are present in the human fetal pituitary, with GHRP-2 stimulating dose-dependent GH release
What the researchers found
GHRP receptor mRNA was detected in human fetal pituitary by RT-PCR, and GHRP-2 stimulated dose-dependent GH release from cultured fetal pituitary cells, demonstrating functional GH secretagogue receptors are present before birth.
Why it matters
Knowing the GH secretagogue system is active in fetal development suggests it plays a role in prenatal growth, which has implications for understanding growth disorders and the safety considerations of GH-releasing peptides in reproductive contexts.
How the study worked
In-vitro study using human fetal pituitary tissue. RT-PCR detected GHRP receptor mRNA expression. Cultured fetal pituitary cells were stimulated with GHRP-2 to demonstrate functional GH release.
What this study cannot tell us
In-vitro study using isolated fetal tissue. Whether GHRP receptor activation plays a physiological role in fetal growth was not established. Limited fetal tissue availability restricts sample sizes.
How to read the evidence
Moderate evidence from a well-designed in-vitro study with both molecular (mRNA detection) and functional (GH release) confirmation in human fetal tissue.
When this study was published
Published in 1998. The role of ghrelin/GHS-R in fetal development has been further studied, confirming early developmental expression of this receptor system.
The bigger picture
Growth hormone is crucial for prenatal development. The finding that fetal pituitary cells already respond to GH-releasing peptides suggests this signaling pathway is important from very early in development, not just after birth.
Questions still open
- Does endogenous ghrelin activate fetal pituitary GHRP receptors to regulate prenatal growth?
- Could GHRP receptor dysfunction contribute to intrauterine growth restriction?
- At what gestational age do GHRP receptors first appear?
Common questions
Why does it matter that fetuses have these receptors?
Is this related to ghrelin?
Read the original research
Human fetal pituitary expresses functional growth hormone-releasing peptide receptors.
The Journal of clinical endocrinology and metabolism, 83(1), 174-8
Citation
Shimon, I; Yan, X; Melmed, S. (1998). Human fetal pituitary expresses functional growth hormone-releasing peptide receptors.. The Journal of clinical endocrinology and metabolism, 83(1), 174-8.