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Suprachiasmatic nucleus lesion increases corticosterone secretion
R M Buijs1, A Kalsbeek, T P van der Woude
1Neurosciences Loeb Medical Research Institute, Ottawa Civic Hospital, Ontario, Canada.
The American Journal of Physiology
|June 1, 1993
Summary
The suprachiasmatic nucleus (SCN) inhibits corticosteroid secretion, contrary to previous assumptions. SCN-lesioned rats showed elevated corticosteroid levels and heightened stress responses, confirming the SCN's inhibitory role.
Area of Science:
- Neuroendocrinology
- Circadian Rhythms
- Stress Response
Background:
- The suprachiasmatic nucleus (SCN) regulates the diurnal rhythm of corticosteroid secretion.
- Vasopressin from the SCN may inhibit corticosteroid secretion in the hypothalamus.
- The SCN's role in corticosteroid regulation, particularly during the day, requires further investigation.
Purpose of the Study:
- To investigate the hypothesis that the SCN acts as an inhibitory system for corticosteroid secretion during the day.
- To determine the effect of SCN lesions on corticosteroid levels and stress responses in rats.
Main Methods:
- Comparison of plasma corticosteroid levels in intact and SCN-lesioned rats.
- Exposure of animals to mild stress during morning and evening periods.
- Monitoring of corticosteroid level changes in response to stress.
Main Results:
- SCN-lesioned rats exhibited higher baseline morning corticosteroid levels compared to intact controls.
- SCN-lesioned rats showed significantly higher corticosteroid responses to stress, both in the morning and evening.
- These findings suggest an inhibitory influence of the SCN on corticosteroid secretion.
Conclusions:
- The SCN plays an inhibitory role in regulating corticosteroid secretion.
- The study provides evidence for the SCN's function in modulating the stress response.
- The findings contribute to understanding the complex interplay between the SCN and the hypothalamic-pituitary-adrenal axis.