The Effect of Moderate Heat on Rat Pituitary ACTH Cells: Histomorphometric, Immunofluorescent and Hormonal Study

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In areas with moderate continental climate, increased average ambient temperature during the summer represents a stressogenic factor that affects the hypothalamo-pituitaryadrenocortical axis in mammals. Therefore, we wanted to examine the effects of 4 days of constant exposure to moderately elevated ambient temperature (35 ± 1oC) on the histomorphometric and immunofl uorescent characteristics, as well as on the hormonal secretion of pituitary corticotropes (ACTH) cells in adult male rats. In comparison with the controls kept at 20 ± 2oC, a signifi cant increase (p<0.05) of the absolute and relative pituitary weight (23.1% and 36.1%, respectively) was registered after exposure to heat. The localization, as well as the shape of the ACTH cells in the heat exposed group was not signifi cantly altered, but their immunopositivity was weaker. After 4 days of heat exposure, a weaker signal confi rmed the relative fl uorescence intensity of the ACTH cells (15.3%, p<0.05). In heat exposed rats, an increase of the cellular and nuclear volumes of immunolabelled ACTH cells and decrease of their volume density (6.9%, 14.3% and 20.0%, respectively; p<0.05) was registered. Observed histomorphometric and immunofl uorescent features of the pituitary ACTH cells were in accordance with the increased (p<0.05) value of plasma adrenocorticotropic hormone (ACTH) by 23.7% compared to the control rats. It can be concluded that the 4-day exposure to moderately elevated ambient temperature intensifi es pituitary ACTH secretion in adult male rats.

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  • 1. Djordjevic J Cvijic G Davidovic V: Different activation of ACTH and corticosterone release in response to various stressors in rats. Physiol Res 2003 52:67-72.

  • 2. Bocheva A Dzambazova E Hadjiolova R Traikov L Mincheva R Bivolarski I: Effect of Tyr-MIF-1 peptides on blood ACTH and corticosterone concentration induced by three experimental models of stress. Auton Autacoid Pharmacol 2008 28:117-123.

  • 3. Van de Kar LD Blair ML: Forebrain pathways mediating stress-induced hormone secretion. Front Neuroendocrinol 1999 20:1-48.

  • 4. Jasnic N Djordjevic J Djurasevic S Lakic I Vujovic P Spasojevic N Cvijic G: Specifi c regulation of ACTH secretion under the infl uence of low and high ambient temperature- The role of catheholamines and vasopressin. J Therm Biol 2012 37:469-474.

  • 5. Koko V Djordjevic J Cvijic G Davidovic V: Effect of the acute heat stress on rat adrenal glands. A morphological and stereological study. J Exp Biol 2004 207:4225-4230.

  • 6. De Kloet ER: Brain corticosteroid receptor balance and homeostatic control. Front Neuroendocrinol 1991 12:95-164.

  • 7. Koko V Djordjevic J Cvijic G Davidovic V: Effect of the acute heat stress on the rat pituitary gland. Morphological and stereological study. J Therm Biol 2006 31:394-399.

  • 8. Jasnic N Korac A Velickovic K Golic I Djordjevic J Djurasevic S Djordjevic I Vujovic P Cvijic G: The effect of acute heat exposure on rat pituitary corticotroph activation: the role of vasopressin. Folia Histochem Cytobiol 2010 28:507-512.

  • 9. Petrovic-Kosanovic D Velickovic K Koko V Jasnic N Cvijic G Cakic-Milosevic M: Effect of acute heat stress on rat adrenal cortex - a morphological and ultrastructural study. Cent Eur J Biol 2012 7:311-619.

  • 10. Brandenberger G Follenius M Di Nisi J Libert JP Simon C: Amplifi cation of nocturnal oscillations in PRA and aldosterone during continuous heat exposure. J Appl Physiol 1989 66:1280-1286.

  • 11. Gjuladin T: The infl uence of high environmental temperature and diabetes on the hormonal state in rats. Master thesis Skopje Macedonia. 2004

  • 12. Popovska-Perčinić F Ajdžanović V Dinevska-Kofkarovska S Jordanova M Trifunović S Šošić-Jurjević B Milošević V: Morphofunctional characteristics of pituitary corticotropes in an animal model of heat stress. J Med Biochem 2011 30:1-5.

  • 13. Mitev S Dinevska-Kjovkarovska S Miova B: Effect of acclimation to high environmental temperature on the activity of hepatic glycogen phosphorylase (a+b and a) liver glycogen content and blood glucose level in rats. J Therm Biol 2005 30:563-568.

  • 14. Sternberger LA Hardy PHJ Cuculius JJ Meye HG: The unlabelled antibody enzyme method of immunohistochemistry. Preparation and properties of soluble antigen-antibody complex (horseradish peroxidase-antihorseradish peroxidase) and its use in identifi cation of spirochetes. J Histochem Cytochem 1970 18:315-333.

  • 15. Starcevic V Milosevic V Brkic B Severs W: Effects of centrally applied somatostatin on pituitary adrenocorticotropes in female rats. Pharmacology 2000 60: 203-207.

  • 16. Medigović I Živanović J Ajdžanović V Nikolić-Kokić A Stanković S Trifunović S Milošević V Nestorović N: Effects of soy phytoestrogens on pituitary-ovarian function in middle-aged female rats. Endocrine 2015 50:764-776.

  • 17. Ajdžanović V Jarić I Živanović J Filipović B Ristić N Miler M Milošević V: Testosterone application decreases the capacity for ACTH and corticosterone secretion in a rat model of the andropause. Acta Histochem 2015 117:528-535.

  • 18. Ajdžanović V Šošić-Jurjević B Filipović B Trifunović S Brkić D Sekulić M Milošević V: Genistein affects the morphology of pituitary ACTH cells and decreases circulating levels of ACTH and corticosterone in middle-aged male rats. Biol Res 2009 42:13-23.

  • 19. Ajdžanović V Šošić-Jurjević B Filipović B Trifunović S Milošević V: Daidzein effects on ACTH cells: immunohistomorphometric and hormonal study in an animal model of the andropause. Histol Histopathol 2011 26:1257-1264.

  • 20. Milošević V Todorović D Veličković M Ristić N Ušćebrka G Knežević V Ajdžanović V: Immunohistomorphometric features of ACTH cells in juvenile rats after treatment with estradiol or human chorionic gonadotropin. J Med Biochem 2012 31:34-39.

  • 21. Milošević V Trifunović S Filipović B Šošić-Jurjević B Pantelić J Perčinić-Popovska F Ajdžanović V: Estradiol and GH cells: Immunohistomorphometric study in an animal model of andropause. Arch Biol Sci 2012 64(2):451-457.

  • 22. Weibel ER: Stereological methods. 1. Practical methods for biological morphometry. New York: Academic Press. 1979 1-415.

  • 23. Poole M Kornegay W: Cellular distribution within the rat adenohypophysis: a morphometric study. Anat Rec 1982 204:45-53.

  • 24. Dallman M: Stress update. Adaptation of the hypothalamic-pituitary-adrenal axis to chronic stress. Trends Endocrinol Metab 1993 4:62-69.

  • 25. Mitev S Buzalkov R Spirovski M: Plasma level of corticosterone total estrogens and total testosterone in rats during acclimation to hypertermic environment (35oC). Gen Comp Endocrinol 1987 66:59-60.

  • 26. Collin A Vaz MJ Le Dividich J: Effects of high temperature on body temperature and hormonal adjustments in piglets. Reprod Nutr Dev 2002 42:45-53.

  • 27. Rousset B Cure M Jordan D Kervran A Bornet H Mornex R: Metabolic alterations induced by chronic heat exposure in the rat: the involvement of thyroid function. Pfl ügers Arch 1984 401:64-70.

  • 28. Cure M: Plasma corticosterone response in continous versus discontinous chronic heat exposure in rat. Physiol Behav 1989 45:1117-1122.

  • 29. Aguilera G Kiss A Lu A Camacho C: Regulation of adrenal steroidogenesis during chronic stress. Endocr Res 1996 22:433-443.

  • 30. Aguilera G Rabadan-Diehl C Luo X Kiss A: Regulation of pituitary ACTH secretion during stress: role of corticotrophin releasing hormone and vasopressin. In: McCarty R. Aguilera G. Sabban E. Kvetansky R. (Eds.) Stress. Molecular Genetics and Neurobiological Advances Gordon and Breach Science Publishers S.A. New York 1996.

  • 31. Filippa V Mohamed F: ACTH cells of pituitary pars distalis of viscacha (Lagostomus maximus maximus): immunohistochemical study in relation to season sex and growth. Gen Comp Endocrinol 2006 146:217-225.

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