Oral GHRP-2 Successfully Releases Growth Hormone in Young Goats | Research

The takeaway

Oral administration of GHRP-2 at 5-10 mg/kg stimulated significant GH release in 1-month-old goats but not 3-month-old goats, demonstrating oral peptide bioactivity varies with age in large animals.

15-minute oral response
Oral GHRP-2 elevated plasma GH within 15 minutes in young goats, demonstrating rapid oral peptide absorption is possible

What the researchers found

Oral GHRP-2 (5-10 mg/kg) stimulated significant GH release in 1-month-old goats (peak at 15 min) but not in 3-month-old goats, demonstrating age-dependent oral peptide bioavailability in ruminants.

Why it matters

Demonstrating oral peptide activity in large animals is important for both agricultural applications (promoting growth) and for understanding oral peptide delivery across species. The age-dependent absorption highlights gut maturation as a factor.

How the study worked

Animal study in goats. GHRP-2 dissolved in saline was administered orally twice at 2-hour intervals to 1-month and 3-month-old goats (n=5-6 per group). Plasma GH levels were measured over time.

What this study cannot tell us

Ruminant digestive system differs significantly from human. Age-dependent response may reflect gut development specific to goats. Relatively high doses required (5-10 mg/kg). Not directly translatable to human oral delivery.

How to read the evidence

Preliminary animal evidence in a non-standard model (goats), demonstrating proof-of-concept for oral peptide activity but with limited translatability to humans.

When this study was published

Published in 1999. Oral peptide delivery research has advanced significantly with new formulation technologies.

The bigger picture

Oral peptide delivery remains a major pharmaceutical challenge. This study shows it's achievable in young animals where gut permeability is higher, supporting research into formulations that might enable oral peptide therapy in humans.

Questions still open

Why does oral peptide absorption decline with age?
Could gut permeability enhancers enable oral GHRP-2 in older animals?
Does this age-dependent absorption apply to human infants vs adults?

Common questions

Can GH peptides work when taken by mouth?

This study shows oral GHRP-2 works in young goats, demonstrating it can survive digestion and reach the bloodstream. However, the doses required were high, and absorption declined with age as the gut matured.

Why did it work in young but not older goats?

Young animals have more permeable intestinal lining, allowing larger molecules like peptides to be absorbed. As the gut matures, permeability decreases, making oral peptide delivery more challenging — a key barrier for human peptide drugs.

Read the original research

Oral administration of peptidergic growth hormone (GH) secretagogue KP102 stimulates GH release in goats.

Domestic animal endocrinology, 16(1), 31-9

View on PubMed ↗

Citation

Hashizume, T; Kawai, M; Ohtsuki, K; Ishii, A; Numata, M. (1999). Oral administration of peptidergic growth hormone (GH) secretagogue KP102 stimulates GH release in goats.. Domestic animal endocrinology, 16(1), 31-9.