Circadian and Ultradian Rhythms of Free Glucocorticoid Hormone Are Highly Synchronized between the Blood, the Subcutaneous Tissue, and the Brain
| Autor: | Stafford L. Lightman, Johannes M. H. M. Reul, Susanne K. Droste, Xiaoxiao Qian, Astrid C E Linthorst |
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| Rok vydání: | 2012 |
| Předmět: |
Male
medicine.medical_specialty Microdialysis Biology 03 medical and health sciences chemistry.chemical_compound Subcutaneous Tissue 0302 clinical medicine Endocrinology Corticosterone Internal medicine medicine Animals Circadian rhythm Rats Wistar 030304 developmental biology Ultradian rhythm 0303 health sciences Pulse (signal processing) Brain Circadian Rhythm Rats 3. Good health chemistry Free fraction Glucocorticoids-CRH-ACTH-Adrenal 030217 neurology & neurosurgery Glucocorticoid medicine.drug Hormone |
| Zdroj: | Endocrinology Qian, X, Droste, S K, Lightman, S L, Reul, J M H M & Linthorst, A C E 2012, ' Circadian and Ultradian Rhythms of Free Glucocorticoid Hormone Are Highly Synchronized between the Blood, the Subcutaneous Tissue, and the Brain ', Endocrinology, vol. 153, no. 9, pp. 4346-4353 . https://doi.org/10.1210/en.2012-1484 |
| ISSN: | 1945-7170 0013-7227 |
| Popis: | Total glucocorticoid hormone levels in plasma of various species, including humans, follow a circadian rhythm that is made up from an underlying series of hormone pulses. In blood most of the glucocorticoid is bound to corticosteroid-binding globulin and albumin, resulting in low levels of free hormone. Although only the free fraction is biologically active, surprisingly little is known about the rhythms of free glucocorticoid hormones. We used single-probe microdialysis to measure directly the free corticosterone levels in the blood of freely behaving rats. Free corticosterone in the blood shows a distinct circadian and ultradian rhythm with a pulse frequency of approximately one pulse per hour together with an increase in hormone levels and pulse height toward the active phase of the light/dark cycle. Similar rhythms were also evident in the subcutaneous tissue, demonstrating that free corticosterone rhythms are transferred from the blood into peripheral target tissues. Furthermore, in a dual-probe microdialysis study, we demonstrated that the circadian and ultradian rhythms of free corticosterone in the blood and the subcutaneous tissue were highly synchronized. Moreover, free corticosterone rhythms were also synchronous between the blood and the hippocampus. These data demonstrate for the first time an ultradian rhythm of free corticosterone in the blood that translates into synchronized rhythms of free glucocorticoid hormone in peripheral and central tissues. The maintenance of ultradian rhythms across tissue barriers in both the periphery and the brain has important implications for research into aberrant biological rhythms in disease and for the development of improved protocols for glucocorticoid therapy. |
| Databáze: | OpenAIRE |
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