Pharmacological Demarcation of the Growth Hormone, Gut Motility and Feeding Effects of Ghrelin Using a Novel Ghrelin Receptor Agonist
Bibliographic record
Abstract
The peptide hormone ghrelin exerts a wide spectrum of activities including the stimulation of GH release, feeding, and gastrointestinal motility, purportedly via the activation of a common receptor, GH secretagogue receptor (since renamed the GRLN-R) The aim of the present study was to determine whether these effects can be separated pharmacologically. Tranzyme Pharma (TZP)-101 is a small-molecule agonist with potent binding affinity (inhibitory constant = 16 nm) and full agonist activity (EC50 = 29 nm, maximum response = 111%) at the human recombinant GRLN-R. Pharmacokinetic profiling of TZP-101 in rat determined a plasma elimination half-life of 99 min and low blood-brain barrier permeability (0.09%). The pharmacological response to TZP-101, administered centrally [intracerebroventricular (icv)] or peripherally (iv), was evaluated in comparison with that of acylated ghrelin. Thus, TZP-101 (iv) accelerated gastric emptying of a liquid meal (2% methylcellulose) similarly to ghrelin (iv). IAlso, TZP-101 (icv) stimulated spontaneous, cumulative food intake in a similar manner to ghrelin (icv). However, unlike ghrelin, TZP-101 did not elicit significant GH release on either central or peripheral administration. Moreover, TZP-101 did not alter ghrelin-induced GH release. n total, these data demonstrate that the GH response can be pharmacologically demarcated from the orexigenic and gastrointestinal responses to ghrelin in rats. The observation that the centrally mediated orexigenic response and the peripherally mediated gastric motility response are pharmacologically associated is consistent with the classification of ghrelin as a brain-gut peptide, whereas the additional action of ghrelin to stimulate GH release (possibly via a distinct signaling pathway) may be considered a complementary mechanism to harmonize somatic growth and body composition with the regulation of energy homeostasis.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".