Regional distribution of immunoreactive prolactin-releasing peptide in the human brain

Regional distribution of prolactin-releasing peptide (PrRP) in the human brain was studied by radioimmunoassay. The antiserum raised against human PrRP-31 in a rabbit was used in the assay, which showed 100% cross reaction with PrRP-20 and no significant cross reaction with other peptides. The highest concentrations of immunoreactive-PrRP were found in hypothalamus (912 +/- 519 fmol/g wet weight, n = 6, mean +/- SEM), followed by medulla oblongata (496 +/- 136 fmol/g wet weight) and thalamus (307 +/- 117 fmol/g wet weight). On the other hand, immunoreactive-PrRP was not detected in frontal lobe or temporal lobe (<50 fmol/g wet weight). Sephadex G50 column chromatography of the immunoreactive-PrRP in the hypothalamus and medulla oblongata showed three immunoreactive peaks; one peak eluting in the position of PrRP-20, one eluting in the position of PrRP-31 and one eluting earlier. Reverse phase high-performance liquid chromatography (HPLC) of these brain tissue extracts showed a peak eluting in the position of PrRP-20 and PrRP-31. The present study has shown for the first time the presence of immunoreactive-PrRP in the human brain. The immunoreactive-PrRP levels in the human hypothalamus were, however, lower than the levels of other neuropeptides with prolactin-releasing activity, such as thyrotropin-releasing hormone and vasoactive intestinal polypeptide.     

Mannosylerythritol lipid increases levels of galactoceramide in and neurite outgrowth from PC12 pheochromocytoma cells

We report here that a microbial extracellular glycolipid,mannosylerythritol lipid (MEL), induces the outgrowth ofneurites from and enhances the activity of acetylcholinesterase(AChE) in PC12 pheochromocytoma cells. Furthermore, treatment ofPC12 cells with MEL increased levels of galactosylceramide(Gal1-1Cer; GalCer). Exposure of PC12 cells to exogenous GalCer caused the dose-dependent outgrowth ofneurites. By contrast, treatment of PC12 cells with nerve growthfactor (NGF) did not increase the level of GalCer in the cells. The neurite-related morphological changes induced by GalCerdifferend from those induced by NGF, indicating differencesbetween the signal transduction pathways triggered by NGF and by GalCer.Both authors contributed equally to this work.     

Decreased bodyweight without rebound and regulated lipoprotein metabolism by gymnemate in genetic multifactor syndrome animal

Objective: The aim of this work was to find obesity control method without rebound. In our previous studies, gymnemate extracted from Gymnema sylvestre, inhibited oleic acid absorption. The Otsuka Long-Evans Tokushima Fatty (OLETF) rat, a genetic multifactor syndrome model, exhibits progressive overweight, hyperlipidemia and hyperglycemia. The effect of gymnemate on obesity in OLETF was investigated. Methods: Three groups were divided (n = 4–8): (1) OLETF-gymnemate, gymnema water extract (containing gymnemate) diet (62.5 g/kg) and water (2.5 g/kg) were supplied 2 weeks from 26–28 weeks, following it general diet and water were fed 3 weeks to observe if it rebound, (2) OLETF-control and (3) the counterpart Long-Evans Tokushima Otsuka rats as normal-control. Results: With gymnemate treatment, the food and water intake were decreased about 1/3 and 2/3, along with body weight reduced 57.2± 6.4 and 75.5± 6.3 g during 1 and 2 weeks respectively. In the end of experiment (3 weeks after gymnemate withdrawal), the body weight was decreased to no significant difference with normal-control. The total cholesterol was decreased about 1/3, moreover LDL+VLDL (low-density and very-low-density lipoprotein) cholesterol decreased about 1/2. The proportion of HDL (high-density lipoprotein) cholesterol to the total cholesterol was increased. The serum triglyceride was decreased to the 1/4 of OLETF control. The level of serum cholesterol and triglyceride was no significant difference in gymnemate group with normal group. Conclusion: Supplementation with gymnemate promotled weight loss by its ability to reduce hyperlipidemia, which was no withdrawal rebound: an important discovery. Supplementation with gymnemate is a novel therapeutic tool for weight management, especially in multifactor syndrome.     

Fluorine-18 (18F)-labeled retinoid x receptor (RXR) partial agonist whose tissue transferability is affected by other RXR ligands

Bexarotene (1), a retinoid X receptor (RXR) agonist approved for the treatment of cutaneous T cell lymphoma (CTCL), was reported to migrate into baboon brain based on findings obtained by positron emission tomography (PET) with a ¹¹C-labeled tracer. However, co-administration of non-radioactive 1 had no effect on the distribution of [¹¹C]1, probably due to non-specific binding of 1 as a result of its high lipophilicity. Here, we report a fluorine-18 (¹⁸F)-labeled PET tracer [¹⁸F]6 derived from RXR partial agonist CBt-PMN (2), which has lower lipophilicity and weaker RXR-binding ability than [¹¹C]1. The concomitant administration of 1 or 2 with [¹⁸F]6 with resulted in decreased accumulation of [¹⁸F]6 in liver, together with increased brain uptake and increased accumulation in kidney and muscle, as visualized by PET. A plausible explanation of these findings is the inhibition of [¹⁸F]6 uptake into the liver by concomitantly administered 1 or 2, leading to an increase in blood concentration of [¹⁸F]6 followed by increased accumulation in other tissues.     

Cloning and expression of cDNA encoding mouse tyrosinase.

We have isolated a pigment cell-specific cDNA clone from a B16 mouse melanoma cDNA library by differential hybridization. The mRNA of isolated cDNA is highly expressed in B16 melanoma cells and in black mouse (C57BL/6) skin, but is not detectable in mouse neuroblastoma cells nor in K1735 mouse amelanotic melanoma cells. The protein sequence deduced from the nucleotide sequence of the cloned cDNA shows significant similarity to the entire region of Neurospora tyrosinase. To know the identity of cDNA, we transfected K1735 amelanotic melanoma and COS-7 cells with the cDNA carried in a simian virus 40 vector (pKCRH2). We confirmed that the isolated cDNA encodes mouse tyrosinase by immunofluorescence staining of transfected cells using two different anti-T4-tyrosinase monoclonal antibodies. Tyrosinase is composed of 513 amino acids with a molecular weight of 57,872 excluding a hydrophobic signal peptide of 24 amino acids.     

Son Is Essential for Nuclear Speckle Organization and Cell Cycle Progression

Subnuclear organization and spatiotemporal regulation of pre-mRNA processing factors is essential for the production of mature protein-coding mRNAs. We have discovered that a large protein called Son has a novel role in maintaining proper nuclear organization of pre-mRNA processing factors in nuclear speckles. The primary sequence of Son contains a concentrated region of multiple unique tandem repeat motifs that may support a role for Son as a scaffolding protein for RNA processing factors in nuclear speckles. We used RNA interference (RNAi) approaches and high-resolution microscopy techniques to study the functions of Son in the context of intact cells. Although Son precisely colocalizes with pre-mRNA splicing factors in nuclear speckles, its depletion by RNAi leads to cell cycle arrest in metaphase and causes dramatic disorganization of small nuclear ribonuclear protein and serine-arginine rich protein splicing factors during interphase. Here, we propose that Son is essential for appropriate subnuclear organization of pre-mRNA splicing factors and for promoting normal cell cycle progression.