Mk-677

NEW FINDINGS: What is the main observation in this case? Co-administration of LGD-4033 and MK-677 increased body mass, lean mass and fat mass, while negatively impacting bone, serum lipids, liver enzymes, testosterone (total and free) and, probably, follicle-stimulating hormone. What insights does it reveal? Our cross-sectional data imply that these compounds might alter intramuscular androgenic hormone and receptor concentrations along with promoting muscular strength, when compared with previously published data from trained males...

Selective Androgen Receptors Modulators (SARMs) are a new class of doping drugs that emerged in sport since 2008. Easy access on the Internet also leads to their misuse by amateurs. It seems important for a laboratory of toxicology to develop a targeted screening of SARMs, given their health risks. A method has been developed and validated for the analysis in hair of 9 SARMs (AC262536, ACP-105, andarine, LGD-4033, MK-0773, MK 677, ostarine, RAD 410 and S23) and 2 other metabolic modulators (GW501516, SR9009), using liquid chromatography coupled to tandem mass spectrometry...

Selective androgen receptor modulators (SARMs) are compounds with specific androgenic properties that have been investigated for the treatment of conditions such as muscle wasting disease. The reported androgenic properties have resulted in their use by athletes, and consequently they have been on the World Anti-Doping Agency prohibited list for more than a decade. To minimise the chance of an unattended positive doping test and to avoid potential serious health problems, adequate screening methods for the detection of a wide range of SARMs in these supplements is necessary...

Ghrelin is a peptide hormone whose effects are mediated by the growth hormone secretagogue receptor subtype 1a (GHS-R1a), mainly expressed in the brain but also in kidneys. The hypothesis herein raised is that GHS-R1a would be player in the renal contribution to the neurogenic hypertension pathophysiology. To investigate GHS-R1a role on renal function and hemodynamics, we used Wistar (WT) and spontaneously hypertensive rats (SHR). First, we assessed the effect of systemically injected vehicle, ghrelin, GHS-R1a antagonist PF04628935, ghrelin plus PF04628935 or GHS-R1a synthetic agonist MK-677 in WT and SHR rats housed in metabolic cages (24 h)...

PURPOSE: Growth hormone secretagogues (GHSs) possess the ability to release growth hormone (GH) in the body. This study aimed to investigate the effects of MK-677, an orally active GHS, on somatic growth in rats. MATERIALS AND METHODS: The serum levels of GH were measured after oral administration of MK-677 to confirm GH stimulatory effects. Body weight, body length, tibia length, epiphyseal plate width, and serum levels of insulin-like growth factor (IGF)-I were measured after oral administration of 4 mg/kg of MK-677 for 6 weeks to investigate growth-promoting effects...

Some growth hormone secretagogues act as agonists at the ghrelin receptor and have been described as "ago-allosteric" ligands because of an ability to also modulate the maximum efficacy and potency of ghrelin (Holst et al., 2005). In membranes prepared from cells coexpressing the human ghrelin receptor and the G protein Galpha(o1), N-[1(R)-1, 2-dihydro-1-ethanesulfonylspiro-3H-indole-3,4'-piperidin)-1'-yl]carbonyl-2-(phenylmethoxy)-ethyl-2-amino-2-methylpropanamide (MK-677), growth hormone-releasing peptide 6 (GHRP-6), and the 2(R)-hydroxypropyl derivative of 3-amino-3-methyl-N-(2,3,4,5-tetrahydro-2-oxo-1-([2'-(1H-tetrazol-5-yl) (1,1'-biphenyl)-4-yl]methyl)-1H-1-benzazepin-3(R)-yl)-butanamide (L-692,585) each functioned as direct agonists, and each displayed higher efficacy than ghrelin...

BACKGROUND: In animals, insulin-like growth factor-1 (IGF-1) increases clearance of beta-amyloid, a pathologic hallmark of Alzheimer disease (AD), from the CNS. Serum IGF-1 level decreases with age, and shows a further decrease in AD. We examined whether the growth hormone secretagogue MK-677 (ibutamoren mesylate), a potent inducer of IGF-1 secretion, slows the rate of progression of symptoms in patients with AD. METHODS: A double-blind, multicenter study was conducted in which 563 patients with mild to moderate AD were randomized to receive MK-677 25 mg or placebo daily for 12 months...

BACKGROUND: Growth hormone secretion and muscle mass decline from midpuberty throughout life, culminating in sarcopenia, frailty, decreased function, and loss of independence. The decline of growth hormone in the development of sarcopenia is one of many factors, and its etiologic role needs to be demonstrated. OBJECTIVE: To determine whether MK-677, an oral ghrelin mimetic, increases growth hormone secretion into the young-adult range without serious adverse effects, prevents the decline of fat-free mass, and decreases abdominal visceral fat in healthy older adults...

A library of robust ghrelin receptor mutants with single substitutions at 22 positions in the main ligand-binding pocket was employed to map binding sites for six different agonists: two peptides (the 28-amino-acid octanoylated endogenous ligand ghrelin and the hexapeptide growth hormone secretagogue GHRP-6) plus four nonpeptide agonists-the original benzolactam L-692,429 [3-amino-3-methyl-N-(2,3,4,5-tetrahydro-2-oxo-1-([2'-(1H-tetrazol-5-yl) (1,1'-biphenyl)-4-yl]methyl)-1H-1-benzazepin-3(R)-yl)-butanamide], the spiroindoline sulfonamide MK-677 [N-[1(R)-1, 2-dihydro-1-ethanesulfonylspiro-3H-indole-3,4'-piperidin)-1'-yl]carbonyl-2-(phenylmethoxy)-ethyl-2-amino-2-methylpropanamide], and two novel oxindole derivatives, SM-130686 [(+)-6-carbamoyl-3-(2-chlorophenyl)-(2-diethylaminoethyl)-4-trifluoromethyloxindole] and SM-157740 [(+/-)-6-carbamoyl-3-(2, 4-dichlorophenyl)-(2-diethylaminoethyl)-4-trifluoromethyloxindole)]...

Treatment of N-arylisonicotinamides with trifluoromethanesulfonic anhydride triggers intramolecular nucleophilic attack of the aryl ring on the 4-position of the pyridinium intermediate. The products are spirocyclic dihydropyridines which can be converted to valuable spirocyclic piperidines related to biologically active molecules such as MK-677.

Two nonpeptide (L692,429 and MK-677) and two peptide [GH-releasing peptide (GHRP)-6 and ghrelin] agonists were compared in binding and in signal transduction assays: calcium mobilization, inositol phosphate turnover, cAMP-responsive element (CRE), and serum-responsive element (SRE) controlled transcription, as well as arrestin mobilization. MK-677 acted as a simple agonist having an affinity of 6.5 nm and activated all signal transduction systems with similar high potency (0.2-1.4 nm). L-692,429 also displayed a very similar potency in all signaling assays (25-60 nm) but competed with a 1000-fold lower apparent affinity for ghrelin binding and surprisingly acted as a positive allosteric receptor modulator by increasing ghrelin's potency 4- to 10-fold...

Growth hormone (GH) consists of several isoforms. We have studied the proportion, expressed as percentage of total GH concentration, of non-22kDa (non-22K) GH isoforms and 20K GH during 8-week oral treatment with MK-677 25mg daily in 12 obese males. The proportion of non-22K GH isoforms in peak total GH samples after the initial MK-677 administration was higher than that after 2 and 8 weeks (p<0.01 and p<0.05, respectively). In selected non-peak total GH samples after the initial MK-677 administration, however, the proportion of non-22K GH isoforms was similar to that in the peak total GH samples after 2 and 8 weeks...

A series of substituted oxindole derivatives was synthesized and evaluated for growth hormone (GH) releasing activity using cultured rat pituitary cells. (+)-6-Carbamoyl-3-(2-chlorophenyl)-(2-diethylaminoethyl)-4-trifluoromethyloxindole (SM-130686, 37S) was found to have potent activity (EC(50) = 3.0 nM), while the other enantiomer 37R had reduced activity. The absolute configuration of 37S was confirmed by X-ray crystallographic analysis. Compound 37S showed a good pharmacokinetic profile in rats with 28% oral bioavailability at 10 mg/kg and excellent in vivo activity as evidenced by a significant weight gain after 4 days of oral administration at 10 mg/kg twice a day...

SM-130686, an oxindole derivative, is a novel orally active GH secretagogue (GHS) which is structurally distinct from previously reported GHSs such as MK-677, NN703 and hexarelin. SM-130686 stimulates GH release from cultured rat pituitary cells in a dose-dependent manner. Half-maximum stimulation was observed at a concentration of 6.3+/-3.4 nM. SM-130686-induced GH release was inhibited by a GHS antagonist, but not by a GH-releasing hormone antagonist. SM-130686 dose-dependently inhibited the binding of radiolabeled ligand, (35)S-MK-677, to human GHS receptor 1a (IC(50)=1...

The synthetic growth hormone (GH) secretagogue hexarelin has important cardiac effects, that include a reduction of dysfunction in ischemic-reperfused hearts from GH-deficient rats after a chronic treatment and an increase of ejection fraction in acutely treated men. To investigate the mechanisms of its cardiac activity, we studied the effects of hexarelin (1-10 microM) on contractility of rat papillary muscles. We observed, in hexarelin treated papillary muscles, an improved recovery of contractility after anoxia...

GH increases bone turnover and stimulates osteoblast activity. We hypothesized that administration of MK-677, an orally active GH secretagogue, together with alendronate, a potent inhibitor of bone resorption, would maintain a higher bone formation rate relative to that seen with alendronate alone, thereby generating greater enhancement of bone mineral density (BMD) in women with postmenopausal osteoporosis. We determined the individual and combined effects of MK-677 and alendronate administration on insulin-like growth factor I levels and biochemical markers of bone formation (osteocalcin and bone-specific alkaline phosphatase) and resorption [urinary N-telopeptide cross-links (NTx)] for 12 months and BMD for 18 months...

Growth hormone (GH) is of importance for normal bone remodelling. A recent clinical study demonstrated that MK-677, a member of a class of GH secretagogues (GHSs), increases serum concentrations of biochemical markers of bone formation and bone resorption. The aim of the present study was to investigate whether the GHSs, ipamorelin (IPA) and GH-releasing peptide-6 (GHRP-6), increase bone mineral content (BMC) in young adult female rats. Thirteen-week-old female Sprague-Dawley rats were given IPA (0.5 mg/kg per day; n=7), GHRP-6 (0...

Growth Hormone (GH)-releasing peptides (GHRPs) and their non peptidyl analogues are synthetic molecules which exhibit strong, dosedependent and reproducible GH-releasing activity but also significant PRL- and ACTH/cortisol-releasing effects. An influence of these compounds on food intake and sleep pattern has been also shown. The neuroendocrine activities of GHRPs are mediated by specific receptors subtypes that have been identified in the pituitary gland, hypothalamus and various extra-hypothalamic brain regions with (125)I-Tyr-Ala-hexarelin, an octapeptide of the GHRP family...

Chromatographic separations of new growth hormone secretagogue compounds were developed to support structure-activity relationship (SAR) studies in conjunction with lead optimization. These new compounds differed from Merck's MK-677 by having two chiral centers and thus diastereomeric mixtures were generated. Separation of initial compounds in the SAR was achieved on a Kromasil C18 column using an ammonium acetate buffer and acetonitrile. However, additional candidates were not separable on C18 columns and a chiral Kromasil CHI-DMB column was used to resolve the diastereomeric compounds...

OBJECTIVE: Growth hormone (GH) treatment decreases total body fat while this effect has not yet been documented for the oral GH secretagogue MK-677. In the present study, the effects of MK-677 treatment on serum levels of leptin, thyroid hormones and testosterone were determined. DESIGN: This was a randomized, double-blind, and parallel study. Twenty-four healthy obese males, 19-49 years of age, with body mass index (BMI) > 30 kg/m2 and a waist:hip ratio > 0...