How Fasting, Stress, and Somatostatin Change a Growth Hormone Peptide's Appetite Effect
The GH secretagogue KP-102 stimulated eating in fed rats but not in fasted or stressed rats, and somatostatin blocked this effect, revealing complex appetite regulation by GH peptides.
Quick Facts
What This Study Found
KP-102 stimulated food intake in freely-fed but not fasted or stressed rats, and central somatostatin administration blocked this effect, demonstrating state-dependent appetite modulation by GH secretagogues.
Key Numbers
How They Did This
Animal study in rats. KP-102-induced food intake was measured under normal feeding, 24-hour fasting, and post-restraint stress conditions. Somatostatin was administered intracerebroventricularly to test its blocking effect.
Why This Research Matters
Understanding that GH peptides only stimulate appetite under certain conditions helps predict their effects in different patient populations and reveals how the brain integrates hunger signals with metabolic status.
The Bigger Picture
GH secretagogues' appetite effects are mediated through the same system as ghrelin (the hunger hormone, discovered later). Understanding how this system responds to different states helps explain why appetite regulation is so complex and context-dependent.
What This Study Doesn't Tell Us
Rat study with limited translational certainty to humans. Single stress model used. The mechanism by which fasting or stress blocks KP-102's appetite effect was not determined.
Questions This Raises
- ?Why does fasting eliminate KP-102's appetite-stimulating effect?
- ?Does stress-induced appetite suppression override GH secretagogue signaling in humans too?
- ?Is the somatostatin pathway a therapeutic target for appetite disorders?
Trust & Context
- Key Stat:
- State-dependent effect KP-102 only stimulated eating in fed rats — fasting, stress, and brain somatostatin all eliminated its appetite effect
- Evidence Grade:
- Preliminary animal evidence showing clear state-dependent effects, but mechanism not elucidated and human relevance uncertain.
- Study Age:
- Published in 1998. These findings were later understood in the context of ghrelin receptor signaling, as KP-102 acts on what was later identified as the ghrelin receptor.
- Original Title:
- The growth hormone secretagogue KP-102-induced stimulation of food intake is modified by fasting, restraint stress, and somatostatin in rats.
- Published In:
- Neuroscience letters, 255(1), 9-12 (1998)
- Authors:
- Shibasaki, T, Yamauchi, N, Takeuchi, K, Ishii, S, Sugihara, H, Wakabayashi, I
- Database ID:
- RPEP-00492
Evidence Hierarchy
Tests effects in animals (usually mice or rats), not humans.
What do these levels mean? →Frequently Asked Questions
Why would a growth hormone peptide affect appetite?
GH-releasing peptides act on the same receptor as ghrelin, the body's natural hunger hormone. So they can stimulate appetite as a side effect of their GH-releasing action.
Why didn't it work in fasting rats?
When rats are already starving, their hunger signals are maximally activated. The GH peptide couldn't push appetite higher because the system was already at its ceiling, suggesting these peptides work by enhancing, not creating, appetite signals.
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Cite This Study
https://rethinkpeptides.com/research/RPEP-00492APA
Shibasaki, T; Yamauchi, N; Takeuchi, K; Ishii, S; Sugihara, H; Wakabayashi, I. (1998). The growth hormone secretagogue KP-102-induced stimulation of food intake is modified by fasting, restraint stress, and somatostatin in rats.. Neuroscience letters, 255(1), 9-12.
MLA
Shibasaki, T, et al. "The growth hormone secretagogue KP-102-induced stimulation of food intake is modified by fasting, restraint stress, and somatostatin in rats.." Neuroscience letters, 1998.
RethinkPeptides
RethinkPeptides Research Database. "The growth hormone secretagogue KP-102-induced stimulation o..." RPEP-00492. Retrieved from https://rethinkpeptides.com/research/shibasaki-1998-the-growth-hormone-secretagogue
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.