Browse more peptide research, methods and limitations.
Natriuretic peptides have dual clinical potential: as diagnostic/prognostic biomarkers for heart failure and as direct therapeutic agents through vasodilation, diuresis, and suppression of the renin-angiotensin and sympathetic nervous systems.
Chen, H H; Burnett, J C · Review
Endogenous opioid peptides regulate visceral pain sensitivity, gastrointestinal motility, and secretion through mu, delta, and kappa receptors in the brain, spinal cord, and enteric nervous system, with dysfunction potentially underlying IBS symptoms.
Corazziari, E · Review
Sixteen novel cyclotides were identified from three plant species, all sharing the cyclic cystine knot motif that confers exceptional thermal, chemical, and enzymatic stability, with diverse bioactivities including antimicrobial and anti-HIV effects.
Craik, D J; Daly, N L; Bond, T; Waine, C · In Vitro
Circulin A's 3D structure reveals a cyclic cystine knot fold with exposed hydrophobic and positively charged surface patches, providing a structural basis for its membrane-disrupting anti-HIV activity.
Daly, N L; Koltay, A; Gustafson, K R; Boyd, M R; Casas-Finet, J R; Craik, D J · In Vitro
Antimicrobial peptide selectivity follows a balance: moderate hydrophobicity and amphipathicity maximize bacterial killing with minimal human cell toxicity, while excessive hydrophobicity increases toxicity without improving antibacterial activity.
Dathe, M; Wieprecht, T · Review
Periodontal pathogens P. gingivalis and Prevotella spp. produce extracellular proteases that degrade and inactivate antimicrobial peptides, representing a bacterial evasion mechanism against innate immune defenses in the oral cavity.
Devine, D A; Marsh, P D; Percival, R S; Rangarajan, M; Curtis, M A · In Vitro
GH secretagogues have clinically significant non-endocrine effects including cardiovascular protection, orexigenic (appetite-stimulating) activity, sleep architecture improvement, and potential anti-aging properties mediated by widespread GHS receptor distribution.
Ghigo, E; Arvat, E; Broglio, F; Giordano, R; Gianotti, L; Muccioli, G; Papotti, M; Graziani, A; Bisi, G; Deghenghi, R; Camanni, F · Review
The thymic-pituitary axis forms a bidirectional neuroendocrine circuit that deteriorates with age, contributing to immunosenescence. Thymic peptide supplementation may restore immune-endocrine homeostasis in aging.
Goya, R G; Bolognani, F · Review
Aging causes progressive disruption of the pituitary-thymic bidirectional circuit: reduced thymic peptide production, altered pituitary hormone output, and impaired integration between immune and endocrine systems, creating a self-reinforcing decline.
Goya, R G; Brown, O A; Bolognani, F · Review
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.
Hashizume, T; Kawai, M; Ohtsuki, K; Ishii, A; Numata, M · Animal Study
GHRP-6 excited most arcuate nucleus neurons but had mixed excitatory/inhibitory effects in ventromedial and periventricular hypothalamic nuclei, revealing multi-circuit brain modulation by GH secretagogues.
Hewson, A K; Viltart, O; McKenzie, D N; Dyball, R E; Dickson, S L · In Vitro
BPC-157 attenuated catalepsy and gastric ulcers induced by haloperidol, fluphenazine, and reserpine at both 10 μg/kg and 10 ng/kg doses, demonstrating broad protective effects against neuroleptic side effects.
Jelovac, N; Sikiric, P; Rucman, R; Petek, M; Marovic, A; Perovic, D; Seiwerth, S; Mise, S; Turkovic, B; Dodig, G; Miklic, P; Buljat, G; Prkacin, I · Animal Study
BPC-157 co-administration with chronic diazepam (10 days) prevented tolerance development, maintained anticonvulsant efficacy, and reduced withdrawal seizure severity at both 10 μg/kg and 10 ng/kg doses in rats.
Jelovac, N; Sikiric, P; Rucman, R; Petek, M; Perovic, D; Marovic, A; Anic, T; Seiwerth, S; Mise, S; Pigac, B; Duplancie, B; Turkovic, B; Dodig, G; Prkacin, I; Stancic-Rokotov, D; Zoricic, I; Aralica, G; Sebecic, B; Ziger, T; Slobodnjak, Z · Animal Study
Ipamorelin (18-450 μg/day SC, three daily injections for 15 days) increased longitudinal bone growth rate and body weight dose-dependently in rats, with sustained GH release throughout the treatment period.
Johansen, P B; Nowak, J; Skjaerbaek, C; Flyvbjerg, A; Andreassen, T T; Wilken, M; Orskov, H · Animal Study
STZ-induced diabetes decreased POMC mRNA by significant amounts in the hypothalamic arcuate nucleus and anterior pituitary by 2-4 weeks, with insulin treatment (3 weeks) normalizing expression levels.
Kim, E M; Grace, M K; Welch, C C; Billington, C J; Levine, A S · Animal Study
Leptin and GHRP-6 activate different populations of arcuate nucleus neurons, with limited overlap, indicating independent pathways for fat-derived and peptide-stimulated growth hormone regulation.
Luckman, S M; Rosenzweig, I; Dickson, S L · Animal Study
BNP demonstrates superior sensitivity over ANP for detecting subclinical left ventricular dysfunction, supporting its use as a screening tool for early identification of heart failure risk.
Mair, J; Friedl, W; Thomas, S; Puschendorf, B · Review
Thymosin beta-4 (Tβ4) applied topically or intraperitoneally to full-thickness wounds in rats accelerated skin regrowth by 42% at day 4 and up to 61% at day 7 compared to saline controls. Treated wounds also contracted at least 11% more than controls by day 7. The peptide increased collagen deposition and new blood vessel formation in the wound. In lab assays, thymosin beta-4 stimulated keratinocyte (skin cell) migration 2–3-fold at doses as low as 10 picograms — an extraordinarily small amount.
Malinda, K M; Sidhu, G S; Mani, H; Banaudha, K; Maheshwari, R K; Goldstein, A L; Kleinman, H K ·
Ipamorelin maintained GH-releasing activity during 8 days of methylprednisolone treatment in rats and partially preserved longitudinal bone growth over 15 days despite glucocorticoid-induced growth suppression.
Malmlöf, K; Johansen, P B; Haahr, P M; Wilken, M; Oxlund, H · Animal Study
High-resolution crystal structures of seven macrocyclic HIV protease inhibitors revealed specific binding interactions, demonstrating how cyclic peptide scaffolds can achieve potent enzyme inhibition with improved drug properties.
Martin, J L; Begun, J; Schindeler, A; Wickramasinghe, W A; Alewood, D; Alewood, P F; Bergman, D A; Brinkworth, R I; Abbenante, G; March, D R; Reid, R C; Fairlie, D P · In Vitro
Non-peptide CRF1 receptor antagonists selectively block stress signaling and show anxiolytic and antidepressant effects in animal models, with potential clinical applications spanning anxiety, depression, addiction, and inflammation.
McCarthy, J R; Heinrichs, S C; Grigoriadis, D E · Review
GHRP-2 preserved GH secretory response in 8 children during prednisone therapy, maintaining GH release levels comparable to pre-treatment baseline, suggesting GHRP-2 bypasses glucocorticoid-induced somatostatin excess.
Meacham, L R; Culler, F L; Abdul-Latif, H; Sullivan, K M; Bowers, C Y · Clinical Trial
GH secretagogues offer three clinical futures: oral GH deficiency treatment replacing injections, improved GH deficiency diagnostics, and expanded indications for partial GH insufficiency in aging, obesity, and critical illness.
Micic, D; Casabiell, X; Gualillo, O; Pombo, M; Dieguez, C; Casanueva, F F · Review
PC1 and PC2 follow markedly different activation pathways. PC1 undergoes rapid propeptide cleavage in the endoplasmic reticulum and is further activated by a carboxyl-terminal processing event. PC2, by contrast, has much longer folding times, exits the ER without propeptide cleavage, and requires association with the neuroendocrine-specific protein 7B2 to become catalytically active. The 7B2 protein is internally cleaved into a 21-kDa fragment and a 31-residue carboxy-terminal peptide once the complex reaches the trans-Golgi network. PC2 propeptide removal occurs later in secretory granules, likely through autocatalysis, but without prior 7B2 encounter, PC2 cannot generate an active enzyme. A 36-residue internal segment of 7B2 appears to mediate the critical conformational changes.
Muller, L; Lindberg, I · Review
MK-677 increased bone formation markers at 2 and 12 months in healthy elderly and in hip fracture patients, with sustained IGF-1 elevation, demonstrating prolonged bone-building potential in age-related bone loss.
Murphy, M G; Bach, M A; Plotkin, D; Bolognese, J; Ng, J; Krupa, D; Cerchio, K; Gertz, B J · RCT
Dynorphin A enhanced mitogen-induced proliferation of rat splenocytes and increased IL-2 production, demonstrating immunostimulatory activity for this previously undercharacterized opioid peptide.
Ni, X; Lin, B C; Song, C Y; Wang, C H · In Vitro
Serial BNP measurements detected doxorubicin-induced cardiotoxicity before clinical symptoms or echocardiographic changes in 30 lymphoma patients, with BNP rising progressively with cumulative drug exposure.
Nousiainen, T; Jantunen, E; Vanninen, E; Remes, J; Vuolteenaho, O; Hartikainen, J · Cohort
Structural comparison revealed the cecropin-magainin hybrid has a bent helix with different hydrophobic surface distribution than the cecropin-melittin hybrid, explaining its superior bacterial selectivity and lower human cell toxicity.
Oh, D; Shin, S Y; Kang, J H; Hahm, K S; Kim, K L; Kim, Y · In Vitro
Pulmonary clearance of adrenomedullin was significantly reduced during late-stage sepsis in rats, contributing to ADM accumulation and the hemodynamic collapse of septic shock.
Ornan, D A; Chaudry, I H; Wang, P · Animal Study
BPC-157 significantly attenuated alloxan-induced gastric lesions in rats (200 mg/kg SC) and mice (400 mg/kg IP), reducing lesion severity and accelerating healing over the observation period.
Petek, M; Sikiric, P; Anic, T; Buljat, G; Separovic, J; Stancic-Rokotov, D; Seiwerth, S; Grabarevic, Z; Rucman, R; Mikus, D; Zoricic, I; Prkacin, I; Sebecic, B; Ziger, T; Coric, V; Turkovic, B; Aralica, G; Rotkvic, I; Mise, S; Hahn, V · Animal Study
Sermorelin, a 29-amino-acid synthetic GHRH analog, serves two clinical roles in children: as a diagnostic test for growth hormone deficiency (via single IV dose of 1 μg/kg) and as a treatment (via daily subcutaneous injection of 30 μg/kg at bedtime). As a diagnostic tool, it produced fewer false positives than other provocative tests. As a treatment, it significantly increased height velocity sustained over 12 months, with limited data suggesting benefits persist through 36 months. However, sermorelin cannot detect hypothalamic-origin GH deficiency (since it acts at the pituitary level), and its growth-promoting effects appear somewhat less robust than direct growth hormone (somatropin) therapy at equivalent doses.
Prakash, A; Goa, K L · Review
Endogenous dynorphins in the inner ear interact with NMDA receptors to modulate auditory nerve excitability, and dysregulation of this system may contribute to tinnitus and hyperacusis by altering spontaneous neural activity.
Sahley, T L; Nodar, R H; Musiek, F E · Review
MK-677 increased IGF-1 through both GH-dependent and GH-independent mechanisms, and elevated cortisol through direct adrenal stimulation rather than ACTH, revealing multi-target pharmacology beyond simple GH secretagogue activity.
Schleim, K D; Jacks, T; Cunningham, P; Feeney, W; Frazier, E G; Niebauer, G W; Zhang, D; Chen, H; Smith, R G; Hickey, G · Animal Study
BPC-157 promoted segmental bone defect healing in rabbits with osteogenic activity comparable to IGF-1 and TGF-beta, demonstrating significant bone regeneration through angiogenic and osteoblast-stimulating mechanisms.
Sebecić, B; Nikolić, V; Sikirić, P; Seiwerth, S; Sosa, T; Patrlj, L; Grabarević, Z; Rucman, R; Petek, M; Konjevoda, P; Jadrijević, S; Perović, D; Slaj, M · Animal Study
GHRP-2 activates the female GH axis through three mechanisms: direct pituitary somatotroph stimulation, amplification of endogenous GHRH release, and functional somatostatin withdrawal, explaining its synergy with GHRH.
Shah, N; Evans, W S; Bowers, C Y; Veldhuis, J D · Clinical Trial
Structure-activity analysis identified the amphipathic helix hydrophobic face as essential for antibacterial activity, tryptophan as important for antitumor activity, and specific substitutions that separate antimicrobial potency from hemolytic toxicity.
Shin, S Y; Kang, J H; Hahm, K S · In Vitro
BPC-157 attenuated both MPTP- and haloperidol-induced Parkinson's-like symptoms in mice while simultaneously protecting against gastric lesions caused by these parkinsongenic agents.
Sikiric, P; Marovic, A; Matoz, W; Anic, T; Buljat, G; Mikus, D; Stancic-Rokotov, D; Separovic, J; Seiwerth, S; Grabarevic, Z; Rucman, R; Petek, M; Ziger, T; Sebecic, B; Zoricic, I; Turkovic, B; Aralica, G; Perovic, D; Duplancic, B; Lovric-Bencic, M; Rotkvic, I; Mise, S; Jagic, V; Hahn, V · Animal Study
BPC-157 provided long-lasting cytoprotection lasting days after administration in gastrectomized rats with duodenal ulcers and reflux esophagitis, significantly outlasting ranitidine and sucralfate.
Sikiric, P; Jadrijevic, S; Seiwerth, S; Sosa, T; Deskovic, S; Perovic, D; Aralica, G; Grabarevic, Z; Rucman, R; Petek, M; Jagic, V; Turkovic, B; Ziger, T; Rotkvic, I; Mise, S; Zoricic, I; Sebecic, B; Patrlj, L; Kocman, B; Sarlija, M; Mikus, D; Separovic, J; Hanzevacki, M; Gjurasin, M; Miklic, P · Animal Study
BPC-157 promoted significantly more angiogenesis and granulation tissue formation than H2-blockers, omeprazole, or sucralfate, identifying its primary healing mechanism as enhanced new tissue growth rather than acid suppression.
Sikiric, P; Separovic, J; Anic, T; Buljat, G; Mikus, D; Seiwerth, S; Grabarevic, Z; Stancic-Rokotov, D; Pigac, B; Hanzevacki, M; Marovic, A; Rucman, R; Petek, M; Zoricic, I; Ziger, T; Aralica, G; Konjevoda, P; Prkacin, I; Gjurasin, M; Miklic, P; Artukovic, B; Tisljar, M; Bratulic, M; Mise, S; Rotkvic, I · Animal Study
BPC-157 demonstrates tissue-protective and regenerative effects across gastrointestinal, musculoskeletal, neurological, and cardiovascular systems, consistently accelerating healing through angiogenesis, anti-inflammation, and NO modulation.
Sikiric, P · Review
BPC-157 maintained cytoprotective activity even when prostaglandin synthesis was blocked by indomethacin, unlike standard anti-ulcer agents, indicating prostaglandin-independent protective mechanisms for adaptive cytoprotection against endogenous irritants.
Sikirić, P; Seiwerth, S; Desković, S; Grabarević, Z; Marović, A; Rucman, R; Petek, M; Konjevoda, P; Jadrijević, S; Sosa, T; Perović, D; Aralica, G; Turković, B · Animal Study
Structurally diverse GH secretagogues (peptides and non-peptides) all converge on the GHS receptor, whose cloning predicted the existence of a natural ligand — later identified as ghrelin — with widespread physiological roles beyond GH release.
Smith, R G; Palyha, O C; Feighner, S D; Tan, C P; McKee, K K; Hreniuk, D L; Yang, L; Morriello, G; Nargund, R; Patchett, A A; Howard, A D · Review
MK-677 increased serum leptin levels independent of body fat changes, increased testosterone, and had no effect on thyroid hormones in obese males, revealing metabolic effects dissociated from fat mass changes.
Svensson, J; Carlsson, B; Carlsson, L M; Jansson, J O; Bengtsson, B A · RCT
MK-677 produced mixed lipoprotein effects in obese males: beneficial increases in HDL and decreases in Lp(a), but also unfavorable increases in total cholesterol, LDL, and triglycerides over 8 weeks.
Svensson, J; Jansson, J O; Ottosson, M; Johannsson, G; Taskinen, M R; Wiklund, O; Bengtsson, B A · RCT
GH secretagogues demonstrate three distinct clinical applications: hexarelin cardioprotection, pediatric growth promotion, and ICU catabolic reversal with GHRP-2/TRH combination.
Svensson, J A; Bengtsson, B · Review
Macrocyclic cystine-knot peptides showed antimicrobial activity requiring both the intact circular backbone and disulfide knot; disrupting either eliminated structure and biological activity.
Tam, J P; Lu, Y A; Yang, J L; Chiu, K W · In Vitro
Endogenous thymosin alpha-1 protein and mRNA were detected in rat CNS neurons, astrocytes, and oligodendrocytes, establishing it as a brain-derived peptide that may contribute to neurotrophic signaling.
Turrini, P; Aloe, L · Animal Study
Critical illness causes biphasic GH axis disruption; GH secretagogues + TRH restore physiological pulsatile GH secretion more safely than direct GH replacement, which increased mortality in a large clinical trial.
Van den Berghe, G · Review
Continuous GHRP-2 infusion synchronized the pulsatile release of GH, TSH, and prolactin in critically ill patients, revealing a common hypothalamic regulatory mechanism that can be pharmacologically reactivated.
Van den Berghe, G; Wouters, P; Bowers, C Y; de Zegher, F; Bouillon, R; Veldhuis, J D · Clinical Trial
Adrenomedullin was locally upregulated in cardiac and aortic endothelial and smooth muscle cells during both early (hyperdynamic) and late (hypodynamic) sepsis stages, establishing cardiovascular tissue as a primary source.
Zhou, M; Chaudry, I H; Wang, P · Animal Study