Authors:P. Van As, C. Careghi, V. Bruggeman, O. M. Onagbesan, S. Van der Geyten, V. M. Darras, and E. Decuypere
growthhormone (GH) secretagogue L-692,429 in the chicken. Gen. Comp. Endocrinol. 111 , 186-196.
Pituitary and extrapituitary action sites of the novel nonpeptidyl growthhormone (GH) secretagogue L-692,429 in the chicken
Authors:Anna Ptak, Ewa L. Gregoraszczuk, and J. Rząsa
: role of IGF as mediator of growthhormone 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 growthhormone
Authors:S. Asolkar, N. Sivaprasad, Alaka Deshpande, K. Shah, and R. Mani
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.
Authors:T. Karir, S. Mirapurkar, N. Jyotsana, and N. Sivaprasad
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.
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.
Authors:A. Saboury, H. Ghourchaei, M. Sanati, M. Atri, M. Rezaei-Tawirani, and G. Hakimelahi
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
Authors:A Saboury, M Atri, M Sanati, and M Sadeghi
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.
) 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 growthhormone (GH) and testosterone (T) secretion ( 22 , 24 , 32