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Orvosi Hetilap
Authors: Erika Hubina, Ágnes Tóth, Gábor László Kovács, Judit Dénes, László Kovács, and Miklós Góth

Yang, N., Langenheim, J. F., Wang, X. és mtsai: Activation of growth hormone receptors by growth hormone and growth hormone antagonist dimers: insight into receptor triggering. Mol. Endocrinol

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growth hormone (GH) secretagogue L-692,429 in the chicken. Gen. Comp. Endocrinol. 111 , 186-196. Pituitary and extrapituitary action sites of the novel nonpeptidyl growth hormone (GH) secretagogue L-692,429 in the chicken

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: role of IGF as mediator of growth hormone action. Fertil. Steril. 66 , 235-239. Insulin-like growth factor (IGF)-I and IGF-II stimulate progesterone production by human luteal cells: role of IGF as mediator of growth hormone

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Abstract  

A simple, specific and sensitive Radioimmunoassay (RIA) has been developed for the measurement of Human Growth Hormone (HGH) in serum samples.125I-labelled HGH has been used as a tracer and dextran coated charcoal system employed to separate antibody bound hormone from the unbound one. The assay offers sensitivity of 0.16 ng/ml with a reproductibility of 7% intrassay and inter-assay variations. Serum HGH levels were measured at fasting-resting state and during insulin stimulation test in (1) 15 normal subjects (controls and (2) 31 patients with stunted growth, whereas (3) in 7 acromegalic patients the same were measured at fasting-resting state and after oral glucose administration. This procedure has been used to distinguish dwarfs due to growth hormone deficiency from other conditions unrelated to pituitary disease and to confirm acromegaly.

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Abstract  

Radioimmunoassay (RIA) of human growth hormone (hGH) using125I-labeled tracer prepared from DNA recombinant hGH (r-hGH) and characterization of the tracer in the assay system are described. The radioiodination of r-hGH resulted in high yield of immunoreactive tracer. The immunoreactive fraction could be purified by gel-filtration on sephadex G-75. The quality of radioiodinated tracer of r-hGH has been found to be same as that of the tracer obtained from pituitary hGH (p-hGH) with respect to immunoreactivity, assay sensitivity and RIA standard curve parameters.

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A thermodynamic study on the binding of magnesium with human growth hormone

Consideration of the new extended coordination model solvation parameters

Journal of Thermal Analysis and Calorimetry
Authors: G. Rezaei Behbehani and A. Saboury

Abstract  

The thermodynamic parameters underlying the binding of Mg2+ to the hydrophobic core of human growth hormone, hGH, are determined using isothermal titration calorimetry. The interaction between Mg2+ and hGH (35 μM) was studied at 27°C in NaCl solution. A new solvation model was used to reproduce the enthalpies of Mg2+-hGH interaction over the whole Mg2+ concentrations. The solvation parameters recovered from the new salvation model, were correlated to the structural changes of hGH due to the metal ion interaction.

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Abstract  

Binding properties and structural changes of human growth hormone (hGH) due to the interaction by cobalt ion (Co2+) were done at 27°C in NaCl solution, 50 mM, using different techniques of UV-Vis spectroscopy, circular dichroism (CD), isothermal titration calorimetry (ITC) and differential scanning calorimetry (DSC) techniques. There is a set of three identical and non-interacting binding sites for cobalt ions. The intrinsic association equilibrium constant and the molar enthalpy of binding obtained by ITC are 0.80 mM−1 and −16.70 kJ mol−1, respectively. The intrinsic association equilibrium constant obtained by a standard isothermal titration UV-Vis spectrophotometry method is also 0.79 mM−1, which is in good agreement with the value obtained from ITC. The Gibbs free energy and entropy changes due to the binding of cobalt ion on hGH are −16.67 kJ mol−1 and −0.1 J K−1 mol−1, respectively. Energetic domains analysis by DSC shows that phase transition of hGH in the presence of cobalt occurs at one main transition. Deconvolution of the main transition provides two sub-transitions with different values of the melting point and enthalpy of unfolding (33°C and 164 kJ mol−1 for the first and 49°C and 177 kJ mol−1 for the second, respectively). Interaction of cobalt ions with hGH prevents aggregation by an affect on the hydrophobicity of the protein macromolecule and provide useful information about its structure due to becoming reversible of protein thermal denaturation.

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Abstract  

A simple graphical linear method was introduced for isothermal titration calorimetric data analysis in the protein-ligand interaction. The number of binding sites, the dissociation binding constant and the molar enthalpy of binding site can be obtained by using this new isothermal titration calorimetric data analysis method. The method was applied to the study of the interaction of human growth hormone (hGH) with divalent calcium ion at 27C in NaCl solution, 50 mM. hGH has a set of three identical and independent binding sites for Ca 2+ . The intrinsic dissociation equilibrium constant and the molar enthalpy of binding are 52 μMand -17.4, respectively. Results obtained by this new calorimetric data analysis are in good agreement with results obtained using our previous method.

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) participated in this study. The sample size was based on the LA parameter, because studies have indicated that increased metabolic acidosis in the form of LA accumulation is partly involved in growth hormone (GH) and testosterone (T) secretion ( 22 , 24 , 32

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: Creatine supplementation enhances maximum voluntary isometric force and endurance capacity . Acta Physiol. Scand. 163 , 279 – 287 ( 1998 ) 26. Matsuse H , Nago T , Takano Y , Shiba N : Plasma growth hormone is elevated immediately

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