open access

Vol 48, No 4 (2010)
ORIGINAL PAPERS
Published online: 2011-04-12
Submitted: 2011-12-19
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The effect of acute heat exposure on rat pituitary corticotroph activation: the role of vasopressin.

Nebojsa Jasnic, Aleksandra Korac, Ksenija Velickovic, Igor Golic, Jelena Djordjevic, Sinisa Djurasevic, Iva Djordjevic, Predrag Vujovic, Gordana Cvijic
DOI: 10.2478/v10042-010-0071-6
·
Folia Histochem Cytobiol 2010;48(4):507-512.

open access

Vol 48, No 4 (2010)
ORIGINAL PAPERS
Published online: 2011-04-12
Submitted: 2011-12-19

Abstract

The increased ambient temperature affects the function of hypothalamic-pituitary-adrenal (HPA) axis. Since the correlation among vasopressin (VP), adrenocorticotropic hormone (ACTH) and corticosterone (CORT) responses to various stressors have been long recognized, the aim of this study was to reveal the aforementioned hormones production and morphology of the pituitary gland after exposure to acute heat. Rats were exposed to high ambient temperature (38 °C) for 20 or 60 minutes. The circulating hormones were determined by an ELISA test or chemiluminescence's method. The results obtained show the elevation in ACTH and CORT secretion depending on the duration of heat exposure. The VP concentration increased only after prolonged exposure to heat (60 min). The pituitary morphology was examined by routine and fluorescent immunohistochemistry as well as electron microscopy. Observed changes in the anterior and posterior pituitary well corresponded to circulating hormones, regarding the volume density of ACTH-immunopositive cells, percentage of ACTH immunopositive area v. total area and number of VP-immunopositive containing varicose fibers per total area. Acute heat exposure also induced changes in shapes of ACTH-immunopositive cells. Cells appeared stellate with numerous slender cytoplasmic processes and degranulated, which is the most obvious after 20 min. In addition, immunopositivity of endothelial and anterior pituitary cells for VP suggests its influence on ACTH secretion.

Abstract

The increased ambient temperature affects the function of hypothalamic-pituitary-adrenal (HPA) axis. Since the correlation among vasopressin (VP), adrenocorticotropic hormone (ACTH) and corticosterone (CORT) responses to various stressors have been long recognized, the aim of this study was to reveal the aforementioned hormones production and morphology of the pituitary gland after exposure to acute heat. Rats were exposed to high ambient temperature (38 °C) for 20 or 60 minutes. The circulating hormones were determined by an ELISA test or chemiluminescence's method. The results obtained show the elevation in ACTH and CORT secretion depending on the duration of heat exposure. The VP concentration increased only after prolonged exposure to heat (60 min). The pituitary morphology was examined by routine and fluorescent immunohistochemistry as well as electron microscopy. Observed changes in the anterior and posterior pituitary well corresponded to circulating hormones, regarding the volume density of ACTH-immunopositive cells, percentage of ACTH immunopositive area v. total area and number of VP-immunopositive containing varicose fibers per total area. Acute heat exposure also induced changes in shapes of ACTH-immunopositive cells. Cells appeared stellate with numerous slender cytoplasmic processes and degranulated, which is the most obvious after 20 min. In addition, immunopositivity of endothelial and anterior pituitary cells for VP suggests its influence on ACTH secretion.
Get Citation
About this article
Title

The effect of acute heat exposure on rat pituitary corticotroph activation: the role of vasopressin.

Journal

Folia Histochemica et Cytobiologica

Issue

Vol 48, No 4 (2010)

Pages

507-512

Published online

2011-04-12

DOI

10.2478/v10042-010-0071-6

Bibliographic record

Folia Histochem Cytobiol 2010;48(4):507-512.

Authors

Nebojsa Jasnic
Aleksandra Korac
Ksenija Velickovic
Igor Golic
Jelena Djordjevic
Sinisa Djurasevic
Iva Djordjevic
Predrag Vujovic
Gordana Cvijic

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