Effects of growth hormone and insulin-like growth factor-I on the iron-induced lipid peroxidation in the rat liver and porcine thyroid homogenates.
OBJECTIVE
Growth hormone (GH) and its tissue mediator, insulin-like growth factor-I (IGF-I), are involved in oxidative processes, lipid peroxidation (LPO) included. Bivalent iron (Fe2+) is frequently used to experimentally induce oxidative damage to macromolecules (Fe2++H2O2+H+→Fe3++•OH+H2O). The aim of the study was to evaluate the effect of GH and/or IGF-I on the iron-induced LPO in the rat liver and porcine thyroid homogenates.


METHODS
Rat liver and porcine thyroid homogenates were incubated in presence of GH (100; 10; 1.0; 0.1; 0.01; 0.001; 0.0001 µg/ml) or IGF-I (1000; 100; 10; 1.0; 0.1; 0.01; 0.001; 0.0001 µg/ml) or GH (100 µg/ml)+IGF-I, or FeSO4+H2O2 plus GH and/or IGF-I. The level of LPO was expressed as concentrations of malondialdehyde+4-hydroxyalkenals (MDA+4-HDA) per mg of protein.


RESULTS
GH and/or IGF-I did not change the basal level of oxidative damage to lipids. In the rat liver homogenates, GH did not affect the iron-induced LPO, whereas IGF-I--in the lowest two concentrations--enhanced the process. In porcine thyroid homogenates, GH--in its two lowest concentrations--prevented, whereas in other concentrations, it enhanced the iron-induced LPO. IGF-I, in all used concentrations, enhanced the iron-induced LPO.


CONCLUSIONS
GH and/or IGF-I may reveal prooxidative effects. This fact does not support their application in the treatment of disorders associated with increased oxidative damage.
Kokoszko
Agnieszka
A
Department of Oncological Endocrinology, Medical University of Lodz, and Polish Mother's Memorial Hospital-Research Institute, Lodz, Poland.
Dabrowski
Jan
J
Lewiński
Andrzej
A
Karbownik-Lewińska
Małgorzata
M
D000704:Analysis of Variance; D000818:Animals; D005296:Ferrous Compounds / Q000494:pharmacology*; D013006:Growth Hormone / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects*; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D051381:Rats; D013552:Swine; D013961:Thyroid Gland / Q000187:drug effects* / Q000378:metabolism
D005296:Ferrous Compounds; C020748:ferrous sulfate; D008315:Malondialdehyde; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone