The median eminence detects and responds to circulating prolactin in the male mouse
| Autor: | Siobhan E Kirk, Stephen J. Bunn, David R. Grattan |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Male
endocrine system medicine.medical_specialty Cell Membrane Permeability Receptors Prolactin Endocrinology Diabetes and Metabolism 030209 endocrinology & metabolism Stimulation Biology 03 medical and health sciences Cellular and Molecular Neuroscience 0302 clinical medicine Endocrinology Arcuate nucleus Internal medicine medicine STAT5 Transcription Factor Animals Receptor Neurons Endocrine and Autonomic Systems Prolactin receptor Arcuate Nucleus of Hypothalamus Median Eminence Prolactin Mice Inbred C57BL Median eminence GABAergic hormones hormone substitutes and hormone antagonists 030217 neurology & neurosurgery Immunostaining Signal Transduction |
| Zdroj: | Journal of neuroendocrinology. 31(6) |
| ISSN: | 1365-2826 |
| Popis: | In addition to its established lactational roles prolactin acts on multiple target tissues and its circulating levels are responsive to a range of physiological stimuli. This investigation has used immunohistochemistry to demonstrate that systemic administration of prolactin activates target cells in the arcuate nucleus and median eminence of the male mouse. Prolactin receptor stimulation results in the phosphorylation and thus activation of signal transducer and activator of transcription (STAT)5. Interestingly, while in the arcuate nucleus this response was localized to cell nuclei, the median eminence displayed both nuclear and diffuse, non-nuclear, phospho-STAT5 (pSTAT5) staining. Dual-label immunostaining demonstrated that while the majority of nuclear pSTAT5 within the median eminence was located within vimentin-positive tanycytes, the non-nuclear staining occurred primarily in neuronal (βIII tubulin immunoreactive) elements. This conclusion was supported by the marked reduction of this signal in prolactin-treated mice lacking neuronal prolactin receptors. A smaller reduction was also seen in animals lacking prolactin receptors on GABAergic, but not glutamatergic, neurons. These findings identify a new prolactin target tissue, and in doing so support the proposal that the median eminence has a sensory role in addition to its established secretory function. The physiological significance of this prolactin response is unknown although its rapidity (maximum within 2 min of intraperitoneal injection) suggests it may provide early detection of an increase in circulating prolactin. It is also possibility is that non-nuclear prolactin-generated pSTAT5 in the median eminence may have a local, non-transcriptional, action. To this end we used Evan Blue dye to demonstrate that elevated prolactin appears to reduce median eminence permeability and that this effect is lost in animals lacking neuronal prolactin receptors. This article is protected by copyright. All rights reserved. |
| Databáze: | OpenAIRE |
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