Insulin Modulates Rat Liver Glucocorticoid Receptor
This investigation used cytosol fraction of rat liver to examine the effects of insulin (INS) on functional properties of glucocorticoid receptor (GR). Male Wistar rats (220–250 g b.wt.) were injected with INS (50 µg/200 g b.wt, i.p.) and 18 h after INS administration used for experiments. INS-stimulated dissociation of G-R complexes was significantly increased by 133% compared to control level. However, INS treatment significantly stimulated stability of GR protein by 138% above control value. Furthermore, results show that INS stimulated activation of formed cytosol [3 H] TA-R complexes by 143% in respect to control. [3H]TA-R complexes from INS treated animals could be activated and accumulated at higher rate in cell nuclei of control animals. The physiological relevance of the data was confirmed by INSrelated stimulation of Tryptophan oxigenase (TO) activity. It was observed that INS stimulated TO activity while INS injected to adrenalectomized rats, exhibited less effects compared to control. The results indicate that a glucocorticoid hormone (CORT) enhances INS induced stimulation of TO activity, as evidenced by enhanced enzyme activity. Presented data suggest: that INS treatment leads to modifications of the GR protein and the nuclear components and that INS activates the rat liver CORT signaling pathway which mediates, in part, the activity of TO.
KeywordsGlucocorticoid receptor activation of receptor hormon-receptor complex insulin tryptophan oxigenase
Unable to display preview. Download preview PDF.
This study was supported by Serbian Ministry of Science and Environment Protection (Grant No 1999).
- 14.Isenovic, E., Radojcic, M., Zakula, Z., Ribarac-Stepic, N. (1993) Effects of insulin on the level of glucocorticoid receptors. Med. Rev. 46, 94–96.Google Scholar
- 21.Lowry, H. D., Rosenbrough, J. N., Farr, A. L., Randall, J. R. (1951) Protein measurement with Folin phenol reagent. J. Biol. Chem. 153, 265–275.Google Scholar
- 23.Moore, F., Cramer, F., Knowies, R. (1951) In: Statistics for Medical Students (ed. Backinston, Comp.), Philadelphia.Google Scholar
This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.