Browse more peptide research, methods and limitations.
Prolonged oral MK-677 significantly improved sleep quality by increasing stage 4 (deep sleep) and REM sleep in both young (18-30) and older (65+) adults.
Copinschi, G; Leproult, R; Van Onderbergen, A; Caufriez, A; Cole, K Y; Schilling, L M; Mendel, C M; De Lepeleire, I; Bolognese, J A; Van Cauter, E · RCT
Simultaneous comparison of six peptide biomarkers in heart failure patients identified the best early CHF indicators across NYHA classes I through IV.
Daggubati, S; Parks, J R; Overton, R M; Cintron, G; Schocken, D D; Vesely, D L · Cross Sectional
Octreotide (somatostatin analog) attenuated GH secretagogue-induced Fos expression in the arcuate nucleus, showing somatostatin opposes GHRP action centrally.
Dickson, S L; Viltart, O; Bailey, A R; Leng, G · Animal Study
Three cationic antibacterial peptides purified from lactoferrin's N-terminus showed activity against enterotoxigenic E. coli, with one being particularly potent.
Dionysius, D A; Milne, J M · In Vitro
Low blood pressure responders to mental stress had significantly higher beta-endorphin release than high responders, suggesting endogenous opioids buffer the cardiovascular stress response.
Fontana, F; Bernardi, P; Pich, E M; Boschi, S; De Iasio, R; Spampinato, S; Grossi, G · Clinical Trial
Beta-endorphin, met-enkephalin, and dynorphin B levels changed significantly during acute blood pressure increases in hypertensive patients, alongside ANF and endothelin-1 alterations.
Fontana, F; Bernardi, P; Spampinato, S; Boschi, S; De Iasio, R; Grossi, G · Clinical Trial
BPC-157 protected against lesions from both NO agonists and NO antagonists, suggesting a modulatory rather than one-directional effect on nitric oxide signaling.
Grabarevic, Z; Tisljar, M; Artukovic, B; Bratulic, M; Dzaja, P; Seiwerth, S; Sikiric, P; Peric, J; Geres, D; Kos, J · Animal Study
Mu and delta opioid receptors mediate alcohol's rewarding properties while kappa receptors oppose them, with all three endogenous opioid peptide families playing distinct roles in addiction.
Herz, A · Review
Recombinant chymosin digestion of lactoferrin yielded multiple antimicrobial peptides including lactoferricin B and novel variants with antibacterial activity.
Hoek, K S; Milne, J M; Grieve, P A; Dionysius, D A; Smith, R · In Vitro
Anti-beta-endorphin antibodies blocked suckling-induced prolactin release without affecting tuberoinfundibular dopaminergic neurons, proving beta-endorphin is an essential mediator.
Jaworski, R P; Callahan, P; Janik, J · Animal Study
BPC-157 at 10 µg/kg provided dose-dependent protection against capsaicin-induced rhinitis, reducing mast cell infiltration, degranulation, and inflammatory cell accumulation.
Kalogjera, L; Ries, M; Baudoin, T; Ferencic, Z; Trotic, R; Pegan, B · Animal Study
All five tested opioid peptides enhanced both NK cell and macrophage/monocyte cytotoxic activity when administered by single IP injection in mice.
Kowalski, J · Animal Study
Hexarelin's GH-releasing effect is significantly modulated by somatostatin tone, with somatostatin withdrawal amplifying the GH response to hexarelin.
Massoud, A F; Hindmarsh, P C; Brook, C G · Clinical Trial
GH secretagogue receptors are molecularly confirmed in both pituitary and hypothalamus, using a distinct signal transduction pathway from GHRH.
McKee, K K; Palyha, O C; Feighner, S D; Hreniuk, D L; Tan, C P; Phillips, M S; Smith, R G; Van der Ploeg, L H; Howard, A D · In Vitro
Cold water swimming-induced analgesia is mediated by met-enkephalin acting on spinal delta-2 opioid receptors, as shown by selective receptor antagonist studies.
Mizoguchi, H; Narita, M; Kampine, J P; Tseng, L F · Animal Study
Enkephalins directly modulate the differentiation of normal human keratinocytes in vitro, establishing opioid peptides as regulators of skin cell biology.
Nissen, J B; Kragballe, K · In Vitro
Endurance training and hypobaric hypoxia independently and combinedly alter ANP and BNP gene expression in rat atrial and ventricular tissue.
Perhonen, M; Takala, T E; Vuolteenaho, O; Mäntymaa, P; Leppäluoto, J; Ruskoaho, H · Animal Study
Intranasal GHRP-2 effectively stimulated GH release in children with short stature, demonstrating viability of a needle-free delivery route.
Pihoker, C; Badger, T M; Reynolds, G A; Bowers, C Y · Clinical Trial
GH secretagogues activate hypothalamic neurons and require an intact GHRH system for full in vivo potency, despite being able to release GH directly from the pituitary.
Robinson, I C · Review
BPC-157 enhanced all three major healing processes: granulation tissue formation, angiogenesis, and collagen synthesis.
Seiwerth, S; Sikiric, P; Grabarevic, Z; Zoricic, I; Hanzevacki, M; Ljubanovic, D; Coric, V; Konjevoda, P; Petek, M; Rucman, R; Turkovic, B; Perovic, D; Mikus, D; Jandrijevic, S; Medvidovic, M; Tadic, T; Romac, B; Kos, J; Peric, J; Kolega, Z · Animal Study
Hybrid peptides from cecropin A-magainin 2 and cecropin A-melittin showed antitumor activity, with structure-activity relationships enabling separation of cancer-killing from hemolytic effects.
Shin, S Y; Lee, M K; Kim, K L; Hahm, K S · In Vitro
BPC-157 both protected against NSAID-induced GI lesions and improved chronic adjuvant arthritis, demonstrating simultaneous gastroprotective and anti-inflammatory effects.
Sikiric, P; Seiwerth, S; Grabarevic, Z; Rucman, R; Petek, M; Jagic, V; Turkovic, B; Rotkvic, I; Mise, S; Zoricic, I; Konjevoda, P; Perovic, D; Simicevic, V; Separovic, J; Hanzevacki, M; Ljubanovic, D; Artukovic, B; Bratulic, M; Tisljar, M; Rekic, B; Gjurasin, M; Miklic, P; Buljat, G · Animal Study
BPC-157 demonstrated cytoprotective effects in totally gastrectomized (acid-free) rats, proving its mechanism is independent of acid reduction.
Sikirić, P; Mikus, D; Seiwerth, S; Grabarević, Z; Rucman, R; Petek, M; Jagić, V; Turković, B; Rotkvić, I; Mise, S; Zoricić, I; Perić, J; Konjevoda, P; Perović, D; Jurina, L; Hanzevacki, M; Separović, J; Gjurasin, M; Jadrijević, S; Jelovac, N; Miklić, P; Buljat, G; Marović, A · Animal Study
BPC-157's mucosal protection in stress involves interactions with both adrenergic and dopaminergic neurotransmitter systems.
Sikirić, P; Mazul, B; Seiwerth, S; Grabarević, Z; Rucman, R; Petek, M; Jagić, V; Turković, B; Rotkvić, I; Mise, S; Zoricić, I; Jurina, L; Konjevoda, P; Hanzevacki, M; Gjurasin, M; Separović, J; Ljubanović, D; Artuković, B; Bratulić, M; Tisljar, M; Miklić, P; Sumajstorcić, J · Animal Study
BPC-157 counteracted both L-NAME (NO blocker) and L-arginine (NO donor) effects on gastric mucosa and blood pressure, confirming its role as an NO system modulator.
Sikirić, P; Seiwerth, S; Grabarević, Z; Rucman, R; Petek, M; Jagić, V; Turković, B; Rotkvić, I; Mise, S; Zoricić, I; Konjevoda, P; Perović, D; Jurina, L; Separović, J; Hanzevacki, M; Artuković, B; Bratulić, M; Tisljar, M; Gjurasin, M; Miklić, P; Stancić-Rokotov, D; Slobodnjak, Z; Jelovac, N; Marović, A · Animal Study
Spontaneously hypertensive rats had significantly lower dynorphin A and B levels in the hypothalamus and pituitary compared to normotensive rats.
Tan-No, K; Terenius, L; Silberring, J; Nylander, I · Animal Study
GHRH and GHRPs can restore GH secretion in aging and disease, addressing the visceral fat accumulation and metabolic changes associated with GH decline.
Thorner, M O; Chapman, I M; Gaylinn, B D; Pezzoli, S S; Hartman, M L · Review
Plasma BNP concentration provided superior prognostic value compared to plasma ANP and other established variables in chronic symptomatic left ventricular dysfunction.
Tsutamoto, T; Wada, A; Maeda, K; Hisanaga, T; Maeda, Y; Fukai, D; Ohnishi, M; Sugimoto, Y; Kinoshita, M · Cohort
Continuous GHRH plus GHRP-2 infusion partially restored GH pulsatility and substantially raised IGF-1 levels in critically ill patients with suppressed somatotropic axes.
Van den Berghe, G; de Zegher, F; Veldhuis, J D; Wouters, P; Awouters, M; Verbruggen, W; Schetz, M; Verwaest, C; Lauwers, P; Bouillon, R; Bowers, C Y · Clinical Trial
Prolonged critical illness disrupts spontaneous TSH and prolactin secretion, and GH secretagogue infusion affects these hormones alongside GH stimulation.
Van den Berghe, G; de Zegher, F; Veldhuis, J D; Wouters, P; Gouwy, S; Stockman, W; Weekers, F; Schetz, M; Lauwers, P; Bouillon, R; Bowers, C Y · Clinical Trial
Dynorphin B induces dose-dependent autocrine stimulation of its own gene expression in cardiac myocytes, creating a self-amplifying loop that is exaggerated in cardiomyopathy.
Ventura, C; Pintus, G · In Vitro
GRF and GHRP-2 both require PKC translocation for GH release, while GHRP-6 releases GH through a PKC-independent mechanism in ovine somatotrophs.
Wu, D; Clarke, I J; Chen, C · In Vitro
Intracerebroventricular etorphine increases met-enkephalin release in the spinal cord, and this spinal opioid mechanism accounts for a significant portion of the observed pain relief.
Xu, J Y; Tseng, L F · Animal Study
Lactoferricin B at concentrations up to 50 μg/ml induced dose- and time-dependent apoptosis in THP-1 human monocytic leukemia cells, with reactive oxygen species playing a key mechanistic role.
Yoo, Y C; Watanabe, R; Koike, Y; Mitobe, M; Shimazaki, K; Watanabe, S; Azuma, I · In Vitro
Two novel tetrapeptides, endomorphin-1 (Tyr-Pro-Trp-Phe-NH2) and endomorphin-2 (Tyr-Pro-Phe-Phe-NH2), were identified as potent and selective endogenous agonists of the mu-opioid receptor.
Zadina, J E; Hackler, L; Ge, L J; Kastin, A J · In Vitro
SSTR2 knockout mice showed no growth hormone negative feedback on arcuate nucleus neurons, demonstrating that this receptor subtype is essential for GH autoregulation.
Zheng, H; Bailey, A; Jiang, M H; Honda, K; Chen, H Y; Trumbauer, M E; Van der Ploeg, L H; Schaeffer, J M; Leng, G; Smith, R G · Animal Study
GHS-R type 1a (active) and type 1b (inactive) mRNA was detected in human pituitary tumor tissue and rat GH3 cells via RT-PCR, confirming these tumors express the GHRP receptor.
Adams, E F; Huang, B; Buchfelder, M; Howard, A; Smith, R G; Feighner, S D; van der Ploeg, L H; Bowers, C Y; Fahlbusch, R · In Vitro
Fluid percussion brain injury in newborn pigs impaired opioid-mediated cerebral artery dilation by disrupting prostaglandin release pathways, blunting the normal vasodilatory response.
Al-Turki, A; Armstead, W M · Animal Study
Sequential backbone modifications of ipamorelin produced smaller peptidomimetic compounds that retained potent GH secretagogue activity, advancing the goal of orally active GH-releasing peptides.
Ankersen, M; Johansen, N L; Madsen, K; Hansen, B S; Raun, K; Nielsen, K K; Thogersen, H; Hansen, T K; Peschke, B; Lau, J; Lundt, B F; Andersen, P H · In Vitro
MK-0677 induced c-Fos expression in arcuate nucleus neurons in vivo, confirming direct hypothalamic activation as a mechanism for its GH-releasing effect.
Bailey, A R; Smith, R G; Leng, G · Animal Study
Phenyl piperazine-based peptidomimetics were identified as potent, orally active GH secretagogues by mimicking privileged structural motifs from known GH-releasing compounds.
Barakat, K J; Cheng, K; Chan, W W; Butler, B S; Jacks, T M; Schleim, K D; Hora, D F; Hickey, G J; Smith, R G; Patchett, A A; Nargund, R P · In Vitro
Specific amino acid and peptide preparations enhanced immune responses, increased phagocytic activity, and protected splenocytes from benzene and aflatoxin B1 toxicity.
Belokrylov, G A; Derevnina, O Y; Molchanova, I V; Sorochinskaya, E I · Animal Study
The A118G single-nucleotide polymorphism in the mu opioid receptor gene has an allelic frequency of approximately 10%, with significant differences in distribution across ethnic groups. The variant receptor showed: - Approximately 3x tighter binding of beta-endorphin compared to the common receptor form - Approximately 3x greater potency of beta-endorphin in activating G protein-coupled potassium channels - No altered binding for most other opioid peptides and alkaloid drugs (morphine, heroin, fentanyl, methadone) The specificity of the effect to beta-endorphin (the endogenous peptide) rather than exogenous opioids is notable, as it suggests this variant primarily affects the body's natural opioid signaling rather than drug pharmacology.
Bond, C; LaForge, K S; Tian, M; Melia, D; Zhang, S; Borg, L; Gong, J; Schluger, J; Strong, J A; Leal, S M; Tischfield, J A; Kreek, M J; Yu, L ·
GHRPs release GH through a unique dual and complementary mechanism acting on both the hypothalamus and pituitary, via a specific receptor distinct from the GHRH receptor.
Bowers, C Y · Review
BNP showed prolonged stability at room temperature in blood samples, significantly outlasting ANP stability, making BNP the preferred clinical biomarker for cardiac function assessment.
Buckley, M G; Marcus, N J; Yacoub, M H; Singer, D R · In Vitro
Cerebrospinal fluid levels of arginine vasopressin (AVP) were directly correlated with life history of general aggression and aggression against persons in people with personality disorders. Higher vasopressin in the brain was linked to more aggressive behavior. Importantly, vasopressin levels were inversely correlated with serotonin function (measured by prolactin response to d-fenfluramine), and lower serotonin function was also linked to greater aggression. However, the relationship between vasopressin and aggression remained significant even after accounting for serotonin's influence, suggesting vasopressin has its own independent role in promoting aggressive behavior beyond the well-known serotonin connection.
Coccaro, E F; Kavoussi, R J; Hauger, R L; Cooper, T B; Ferris, C F · Cross Sectional
Pulsatile hexarelin dosing maintained GH-releasing efficacy with modest desensitization, while continuous infusion caused marked attenuation of GH response, supporting intermittent dosing strategies.
Conley, L K; Gaillard, R C; Giustina, A; Brogan, R S; Wehrenberg, W B · Animal Study
Both mutant forms of alpha-synuclein (A53T and A30P), which are linked to early-onset Parkinson's disease, form Lewy body-like fibrils more rapidly than the wild-type protein in test-tube conditions. The A53T mutation produced fibrils fastest. All three forms of alpha-synuclein were disordered at low concentrations, but at higher concentrations they assembled into fibrils and spherical structures characteristic of the brain inclusions seen in Parkinson's patients.
Conway, K A; Harper, J D; Lansbury, P T · In Vitro
NYHA class III heart failure patients had elevated resting beta-endorphin and neurohormone levels, with naloxone-modifiable stress responses, confirming active opioid system involvement in cardiovascular stress regulation.
Fontana, F; Bernardi, P; Pich, E M; Boschi, S; De Iasio, R; Spampinato, S · Clinical Trial
Asymptomatic dilated cardiomyopathy patients had normal resting opioid peptide levels but showed altered opioid peptide responses to mental stress, alongside elevated ANF levels.
Fontana, F; Bernardi, P; Merlo Pich, E; Tartuferi, L; Boschi, S; De Iasio, R; Spampinato, S · Clinical Trial