Pharmaceutical development of glucagon for use in acute hypoglycemia has proved challenging, due in large part to poor solubility, poor stability and aggregate formation. Herein, we describe highly soluble, low aggregating, glucagon conjugates generated through use of the commercially available vitamin B precursor dicyanocobinamide ('corrination'), which retain full stimulatory action at the human glucagon receptor. The modified glucagon analogs were tested in a chemical stability assay in 50 mM phosphate buffer and the percentage of original concentration retained was determined after two weeks of incubation at 37° C.
View Article and Find Full Text PDFGrowth differentiation factor 15 (GDF15) is a contributor to nausea, emesis, and anorexia following chemotherapy via binding to the GFRAL-RET receptor complex expressed in hindbrain neurons. Therefore, GDF15-mediated GFRAL-RET signaling is a promising target for improving treatment outcomes for chemotherapy patients. We developed peptide-based antagonists of GFRAL that block GDF15-mediated RET recruitment.
View Article and Find Full Text PDFObjectives: Oxytocin (OT) has a well-established role in reproductive behaviours; however, it recently emerged as an important regulator of energy homeostasis. In addition to central nervous system (CNS), OT is found in the plasma and OT receptors (OT-R) are found in peripheral tissues relevant to energy balance regulation. Here, we aim to determine whether peripheral OT-R activation is sufficient to alter energy intake and expenditure.
View Article and Find Full Text PDFIntroduced less than two decades ago, glucagon-like peptide-1 receptor agonists rapidly reshaped the field of Type 2 diabetes mellitus (T2DM) care by providing glycaemic control in tandem with weight loss. However, FDA-approved GLP-1 receptor agonists are often accompanied by nausea and emesis and, in some lean T2DM patients, by undesired anorexia. Importantly, the hypophagic and emetic effects of GLP-1 receptor agonists are caused by activation of central GLP-1 receptors.
View Article and Find Full Text PDFCorrination is the conjugation of a corrin ring containing molecule, such as vitamin B (B12) or B12 biosynthetic precursor dicyanocobinamide (Cbi), to small molecules, peptides, or proteins with the goal of modifying pharmacology. Recently, a corrinated GLP-1R agonist (GLP-1RA) exendin-4 (Ex4) has been shown to have reduced penetration into the central nervous system relative to Ex4 alone, producing a glucoregulatory GLP-1RA devoid of anorexia and emesis. The study herein was designed to optimize the lead conjugate for GLP-1R agonism and binding.
View Article and Find Full Text PDFGlucagon-like peptide-1 receptor (GLP-1R) agonists used to treat type 2 diabetes mellitus often produce nausea, vomiting, and in some patients, undesired anorexia. Notably, these behavioral effects are caused by direct central GLP-1R activation. Herein, we describe the creation of a GLP-1R agonist conjugate with modified brain penetrance that enhances GLP-1R-mediated glycemic control without inducing vomiting.
View Article and Find Full Text PDFAim: To develop a conjugate of vitamin B12 bound to the glucagon-like peptide-1 receptor (GLP-1R) agonist exendin-4 (Ex4) that shows reduced penetrance into the central nervous system while maintaining peripheral glucoregulatory function.
Methods: We evaluated whether a vitamin B12 conjugate of Ex4 (B12-Ex4) improves glucose tolerance without inducing anorexia in Goto-Kakizaki (GK) rats, a lean type 2 diabetes model of an understudied but medically compromised population of patients requiring the glucoregulatory effects of GLP-1R agonists without anorexia. We also utilized the musk shrew (Suncus murinus), a mammalian model capable of emesis, to test B12-Ex4 on glycaemic profile, feeding and emesis.
Previous studies identify a role for hypothalamic glia in energy balance regulation; however, a narrow hypothalamic focus provides an incomplete understanding of how glia throughout the brain respond to and regulate energy homeostasis. We examined the responses of glia in the dorsal vagal complex (DVC) to the adipokine leptin and high fat diet-induced obesity. DVC astrocytes functionally express the leptin receptor; in vivo pharmacological studies suggest that DVC astrocytes partly mediate the anorectic effects of leptin in lean but not diet-induced obese rats.
View Article and Find Full Text PDFVideo-assisted hot stage polarized light microscopy of 55 quasienantiomeric pairs, constructed from 22 chiral diarylamides that systematically differ in topology, reveals the structural boundaries of molecular shape to supramolecular assembly.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
October 2008
Background, Aim, And Scope: Large-scale deforestation is occurring in subarctic North America following clearing by salvage logging or insect attack. Numerous shrubs, herbs, and deciduous tree species tend to dominate areas on which stands of white spruce have grown. In the absence of economically advantageous mechanical methods, several herbicides have value in efforts to reforest by planting white spruce.
View Article and Find Full Text PDFFeeding rats diets containing brominated corn oil or di- or tetrabromostearate as the monoglyceride produced changes in fatty acid composition of liver lipids. Those changes associated with the feeding of brominated corn oil or tetrabromostearate could be explained by the accumulation of triglyceride, and the changes associated with the feeding of dibromostearate could result from the proliferation of a membrane system. A unique response to the feeding of diets containing brominated corn oil is an increase in the level of gamma-linolenic acid.
View Article and Find Full Text PDFRats were fed for 35 days diets containing 2% of either brominated corn oil (BCO), monoglyceride of dibromostearate (DBS), monoglyceride of tetrabromostearate (TBS) or a mixture of the two monoglycerides (BMG) which provided proportions of brominated acids comparable to that of the BCO. Hearts from all animals fed BCO were yellow colored and firm in texture. Myocardial cellular degeneration, mild to moderate edema and occasional small necrotic foci were observed.
View Article and Find Full Text PDFRats have been fed diets containing either 0.8% brominated corn oil or 0.5% of the ethyl ester of 9,10-dibromostearate or 9,10,12,13-tetrabromostearate.
View Article and Find Full Text PDFThe incidence of spontaneous mammary tumors in C3H mice at 35 wk was higher in mice fed rations containing cottonseed oil than in mice fed fats of comparable fatty acid composition. The time to 50% (T50) incidence was also shorter in the first group. The fatty acid composition of tissue lipids from mice fed the cottonseed oil showed changes indicating the presence of cyclopropene fatty acids-higher levels of saturates and lower oleate/stearate and palmitoleate/palmitate ratios.
View Article and Find Full Text PDFJ Toxicol Environ Health
April 1982
Tissue Cd levels were determined 1, 2, 4, 8, and 12 wk after weanling rats were provided with food or water containing 1-1000 ng/g Cd as 109CdCl2. No differences in growth rate or organ weight were observed over the concentration range tested. Kidney accumulated the highest concentration of Cd, followed by liver with values one-third to one-fourth those found in the kidney.
View Article and Find Full Text PDFStatistical techniques have been used to establish the extent to which the incidence of spontaneous mammary tumors in C3H mice could be associated with the levels of individual fatty acids in their diets. Eleven different fats and oils and nine mixtures of these fats and oils were selected so that the levels of the nine major fatty acids varied over a reasonable range and were not highly correlated with one another. Tumor incidence was observed in mice raised on diets containing 10% of these different fats.
View Article and Find Full Text PDFTwo experiments of 20 and 40 weeks duration were conducted to determine the effects of feeding dieldrin or PCB (Aroclor 1254) on the reproductive performance of adult White Leghorn males. Dieldrin at the levels used (0, 25, and 50 ppm) produced no significant changes in semen volume, semen concentration, fertility, and hatchability of fertile eggs. Mortality increased with increased levels of dieldrin and appeared related to duration of exposure to the pesticide.
View Article and Find Full Text PDFTwo experiments were conducted to determine the effects of DDE, DDT and calcium on performance of quail. The quail received diets containing 0 or 100 p.p.
View Article and Find Full Text PDFTwo experiments were conducted to determine the effects of dieldrin and calcium on reproductive performance of quail. At 25% egg production the quail received diets containing 0,10 or 25 p.p.
View Article and Find Full Text PDFComp Biochem Physiol B
July 1973