Effect of the Orally Active Growth Hormone Secretagogue MK-677 on Somatic Growth in Rats.

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. RESULTS: Oral administration of MK-677 at 4 mg/kg increased peak GH concentrations by 1.8-fold, compared to baseline. However, oral administration of MK-677 for 6 weeks did not increase body growth or serum levels of IGF-I. At 6 weeks after treatment, the GH response to MK-677 was abolished. Pituitary GH mRNA and hypothalamic GH-releasing hormone mRNA, and GH secretagogue receptor (GHSR) mRNA expression in the pituitary and hypothalamus did not differ between the control and treatment group. Somatostatin (SST) mRNA expression in the hypothalamus was markedly increased in the treatment group, whereas SST receptor (SSTR)-2 mRNA expression in the pituitary gland was decreased. Protein expression of hypothalamic GHSR, SST, and pituitary SSTR-2 showed patterns similar to those for mRNA expression. CONCLUSION: Our results suggest that prolonged administration of MK-677 in rats does not promote growth despite the GH stimulatory effect of MK-677, which may be related to increased expression of SST in the hypothalamus. Further studies are needed to overcome the observed desensitization to GHS.

PG201 downregulates the production of nitrite by upregulating heme oxygenase-1 expression through the control of phosphatidylinositol 3-kinase and NF-E2-related factor 2.

PG201 is an ethanol extract prepared from a specially designed botanical formulation and has previously been shown to contain strong anti-arthritic activities by controlling inflammation and cartilage destruction in two animal models [1,2]. In the present study, we evaluated the effects of PG201 on the expression of heme oxygenase-1 (HO-1). The treatment of Raw264.7 cells (a murine macrophage cell line) and bone marrow-derived macrophages (BMDMs) with PG201 increased the protein and RNA levels of HO-1. The results from a reporter plasmid assay indicated that PG201 induced HO-1 promoter activity through the stress response element present in the two enhancers of the HO-1 promoter. The treatment of cells with PG201 increased the total amount and the nuclear level of NF-E2-related factor 2 (Nrf2). Protein analysis using BMDMs from Nrf2 knockout mice showed that Nrf2 was necessary for the PG201-mediated induction of HO-1 expression. The PG201-mediated induction of these anti-oxidative stress factors was inhibited by a specific inhibitor of phosphatidylinositol 3-kinase (PI3K), but not by inhibitors of p38, ERK and JNK mitogen-activated protein kinases. Furthermore, the results from an experiment involving a specific siRNA and chemical inhibitors for HO-1 showed that the PG201-mediated increase of the HO-1 protein contributed to the suppression of inducible nitric oxide synthase (iNOS) and nitrite production stimulated by lipopolysaccharide. Taken together, these results suggest that PG201 activates Nrf2 through the PI3K signal transduction pathway, increases the expression of HO-1, and subsequently decreases the production of iNOS and nitrite, eventually exerting anti-inflammatory activities.

Effect of Opuntia humifusa supplementation and acute exercise on insulin sensitivity and associations with PPAR-γ and PGC-1α protein expression in skeletal muscle of rats.

This study examined whether Opuntia humifusa (O. humifusa), which is a member of the Cactaceae family, supplementation and acute swimming exercise affect insulin sensitivity and associations with PPAR-γ and PGC-1α protein expression in rats. Thirty-two rats were randomly divided into four groups (HS: high fat diet sedentary group, n = 8; HE: high fat diet acute exercise group, n = 8; OS: 5% O. humifusa supplemented high fat diet sedentary group, n = 8; OE: 5% O. humifusa supplemented high fat diet acute exercise group, n = 8). Rats in the HE and OE swam for 120 min. before being sacrificed. Our results indicated that serum glucose level, fasting insulin level and homeostasis model assessment of insulin resistance (HOMA-IR) in OS were significantly lower compared to those of the HS (p < 0.01, p < 0.05, p < 0.05). In addition, PPAR-γ protein expression in the OS and OE was significantly higher than that of the HS and HE, respectively (p < 0.05, p < 0.01). PGC-1α and GLUT-4 protein expressions in the OS were significantly higher compared to those of the HS (p < 0.05, p < 0.05). From these results, O. humifusa supplementation might play an important role for improving insulin sensitivity through elevation of PPAR-γ, PGC-1α, and GLUT-4 protein expression in rat skeletal muscle.

Dehydrodiconiferyl alcohol isolated from Cucurbita moschata shows anti-adipogenic and anti-lipogenic effects in 3T3-L1 cells and primary mouse embryonic fibroblasts.

A water-soluble extract from the stems of Cucurbita moschata, code named PG105, was previously found to contain strong anti-obesity activities in a high fat diet-induced obesity mouse model. One of its biological characteristics is that it inhibits 3T3-L1 adipocyte differentiation. To isolate the biologically active compound(s), conventional solvent fractionation was performed, and the various fractions were tested for anti-adipogenic activity using Oil Red O staining method. A single spot on thin layer chromatography of the chloroform fraction showed a potent anti-adipogenic activity. When purified, the structure of its major component was resolved as dehydrodiconiferyl alcohol (DHCA), a lignan, by NMR and mass spectrometry analysis. In 3T3-L1 cells, synthesized DHCA significantly reduced the expression of several adipocyte marker genes, including peroxisome proliferator-activated receptor γ (Pparg), CCAAT/enhancer-binding protein α (Cebpa), fatty acid-binding protein 4 (Fabp4), sterol response element-binding protein-1c (Srebp1c), and stearoyl-coenzyme A desaturase-1 (Scd), and decreased lipid accumulation without affecting cell viability. DHCA also suppressed the mitotic clonal expansion of preadipocytes (an early event of adipogenesis), probably by suppressing the DNA binding activity of C/EBPß, and lowered the production level of cyclinA and cyclin-dependent kinase 2 (Cdk2), coinciding with the decrease in DNA synthesis and cell division. In addition, DHCA directly inhibited the expression of SREBP-1c and SCD-1. Similar observations were made, using primary mouse embryonic fibroblasts. Taken together, our data indicate that DHCA may contain dual activities, affecting both adipogenesis and lipogenesis.

Bojungikgitang and banhabaekchulchonmatang in adult patients with tinnitus, a randomized, double-blind, three-arm, placebo-controlled trial--study protocol.

BACKGROUND: Tinnitus is the perception of hearing a sound for which there is no external acoustic source. It is often associated with sudden, temporary hearing loss and has a clear impact on a patient's quality of life. Despite numerous trials, there are no treatments that can be considered well established in terms of providing replicable long-term tinnitus reduction. Complementary and alternative medical approaches have been employed to relieve symptoms of tinnitus. Bojungikgitang and banhabaekchulchonmatang are among the most strongly preferred and widely used herbal medicines for tinnitus in Korea, as they cause very few serious adverse effects.We aim to establish basic clinical efficacy and safety data for bojungikgitang and banhabaekchulchonmatang, which are approved as herbal medications by the Korea Food and Drug Administration in adult patients with tinnitus. METHODS/DESIGN: This study was a randomised, double-blind, placebo-controlled trial with three parallel arms (bojungikgitang, banhabaekchulchonmatang, and a placebo). Participants included in the study met the following criteria: typical conditions of intermittent or continuous tinnitus, for more than three months, with involuntary perceptions of the concept of a sound in the absence of an external source. Participants received bojungikgitang, banhabaekchulchonmatang, or a placebo-drug for eight weeks. The total duration of each arm was eleven weeks. Each participant was examined for signs and symptoms of tinnitus before and after taking medication. Post-treatment follow-up was performed two weeks after the final administration of medication. DISCUSSION: This trial provided evidence for the efficacy and safety of bojungikgitang and banhabaekchulchonmatang in adult patients with tinnitus. The primary outcome measure was the Tinnitus Handicap Inventory, an assessment used to identify difficulties that may be experienced due to tinnitus. The secondary measures were included an Acoustic Examination and the Visual Analogue Scale. We employed the Euro-Qol 5-Dimension and the Health Utilities Index Mark 3, a health-related quality of life questionnaire. Safety was assessed by complete blood cell count, erythrocyte sedimentation rate, blood chemistry, urine analysis, PA chest film, brain computed tomography, otologic examination, and vital signs. TRIAL REGISTRATION: Current Controlled Trials ISRCTN23691284.

Potential analgesic and anti-inflammatory activities of Panax ginseng head butanolic fraction in animals.

The present study reports the potential anti-rheumatoid activity of Panax ginseng head part. P. ginseng-head part BuOH fraction (PGHB) was safe in acute toxicity (LD(50)>5000mg/kg) and inhibited the partially acetic acid-induced writhes (approximately 32%, P<0.05) in mice. PGHB (500mg/kg) inhibited the acetic acid-induced extravasation of Evan's blue dye in mice by approximately 20.6% (P<0.05), and was similar to the suppressive effect of ibuprofen (27.7%) as a positive control drug. Also, PGHB reduced the carrageenan-induced paw edema at 3h after oral administration, and suppressed the production of serum IL-6 in CIA mice. This suggests that PGHB has potential analgesic and anti-inflammatory activities, and will be the supporting evidence for the potential anti-rheumatoid activity of Korean P. ginseng-head.