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Primary Culture of Rat Adrenocortical Cells and Assays of Steroidogenic Functions
Published on: March 12, 2019
Glucocorticoid receptor immunoreactivity in the rat intermediate lobe
L T Bertini1, M M Westphal, R E Kloet
1Institute of Histology and Embryology, University of Geneva Medical School, 1 rue Michel Servet 1211, Geneva 4, Switzerland.
Journal of Neuroendocrinology
|February 13, 2009
Summary
Glucocorticoid receptors (GR) are present in rat pituitary intermediate lobe cells, not just the anterior lobe. This suggests the intermediate lobe is also influenced by glucocorticoid hormones.
Area of Science:
- Endocrinology
- Neuroscience
- Cell Biology
Background:
- The pituitary gland is a key endocrine regulator.
- Glucocorticoids are vital hormones influencing numerous physiological processes.
- The distribution and regulation of glucocorticoid receptors (GR) in the pituitary are crucial for understanding hormonal feedback mechanisms.
Purpose of the Study:
- To investigate the presence and localization of Type II glucocorticoid receptor (GR) immunoreactivity in the rat pituitary gland.
- To examine the effects of adrenalectomy and dexamethasone administration on GR distribution in different pituitary lobes.
- To compare GR levels between the anterior and intermediate lobes of the rat pituitary.
Main Methods:
- Immunocytochemistry using a specific monoclonal antibody for GR detection.
- Light and electron microscopy to visualize GR localization at the cellular and subcellular levels.
- Protein A-gold technique for electron microscopic immunolabeling.
- Quantitative analysis of GR immunoreactive sites.
Main Results:
- GR immunoreactive cells were identified in both the anterior and intermediate lobes of the rat pituitary gland.
- GR was predominantly found in cell nuclei at the light microscopic level.
- Adrenalectomy decreased GR staining intensity in the anterior lobe and altered its cellular distribution, with less pronounced effects in the intermediate lobe.
- Dexamethasone administration reversed these adrenalectomy-induced changes in both lobes.
- Electron microscopy revealed GR localization in both nuclei and cytoplasm, with approximately 40% more immunoreactive sites in the anterior lobe compared to the intermediate lobe.
Conclusions:
- The presence of GR in the intermediate lobe indicates that this pituitary region is directly influenced by glucocorticoid hormones.
- GR regulation in the intermediate lobe appears distinct from, but responsive to, glucocorticoid signaling.
- These findings expand our understanding of glucocorticoid action within the pituitary gland.
