Hybrid GH Secretagogues Combining NN703 and Ipamorelin Features Are Potent In Vitro and In Vivo | Research

The takeaway

Hybrid compounds combining structural elements of the oral GH secretagogue NN703 with ipamorelin's core showed potent GH-releasing activity in cell assays and in live pigs.

Nanomolar + in vivo
Hybrid compounds achieved low nanomolar cell potency AND effective GH release in pigs — both benchmarks needed for drug development

What the researchers found

NN703-ipamorelin hybrid GH secretagogues showed low nanomolar in vitro potency in pituitary cell assays and effective GH release in pigs in vivo, validating the hybrid design approach.

Why it matters

Creating more potent oral GH secretagogues is key to developing practical GH deficiency treatments. Combining proven scaffolds is an efficient drug design strategy.

How the study worked

In-vitro pituitary cell assay (rat) and in-vivo single-dose GH release testing in pigs for a series of NN703-ipamorelin hybrid compounds.

What this study cannot tell us

Short abstract with limited pharmacological detail. Single-dose pig study. Oral bioavailability not confirmed for all hybrids.

How to read the evidence

Preliminary evidence with both in vitro and in vivo validation, though limited by brief reporting and single-dose animal testing.

When this study was published

Published in 2001. NN703 entered clinical trials; the hybrid optimization approach continues to inform GH secretagogue drug design.

The bigger picture

Drug design by combining successful structural elements from different compounds is a proven pharmaceutical strategy. These hybrids represent the ongoing optimization of oral GH secretagogues.

Questions still open

Do the most potent hybrids maintain ipamorelin's selectivity?
Can these achieve oral bioavailability suitable for clinical use?
How do they compare to MK-677 for clinical development?

Common questions

Why combine two existing peptides?

NN703 has oral activity (it can be taken as a pill) while ipamorelin has excellent selectivity (only releases GH). Combining their best features creates compounds with both advantages — oral and selective.

Are these available to use?

Not yet. These are early-stage research compounds being tested for drug development potential. They represent the ongoing optimization work needed before a new drug reaches patients.

Read the original research

Highly potent growth hormone secretagogues: hybrids of NN703 and ipamorelin.

Bioorganic & medicinal chemistry letters, 11(14), 1915-8

View on PubMed ↗

Citation

Hansen, T K; Ankersen, M; Raun, K; Hansen, B S. (2001). Highly potent growth hormone secretagogues: hybrids of NN703 and ipamorelin.. Bioorganic & medicinal chemistry letters, 11(14), 1915-8.