The polyamine stress response: tissue-, endocrine-, and developmental-dependent regulation
V H Gilad1, J M Rabey, Y Kimiagar
1Laboratory of Neuroscience, Research and Development, Assaf Harofeh Medical Center, 70300, Zrifin, Israel. gmgilad@asaf.health.gov.il
Biochemical Pharmacology
|February 13, 2001
Summary
The polyamine stress response (PSR) differs between the brain and peripheral organs during development. Hormonal signals, not neuronal ones, primarily activate the peripheral PSR, while the brain
Area of Science:
- Neuroscience
- Endocrinology
- Cellular Biology
Background:
- The polyamine stress response (PSR) involves transient changes in polyamine metabolism.
- In adults, the brain and liver show increased PSR, while the adrenal gland and thymus show decreased PSR.
- The brain's PSR is unresponsive during early postnatal development.
Purpose of the Study:
- To investigate the developmental regulation of the PSR in the liver, thymus, and adrenal gland.
- To determine if neuronal and hormonal signals can independently activate the PSR.
Main Methods:
- Measuring ornithine decarboxylase (ODC) activity and tissue polyamine concentrations in male Wistar rats.
- Assessing PSR during postnatal development and after adrenalectomy in adult rats.
- Administering restraint stress and dexamethasone to adrenalectomized rats.
Main Results:
- The PSR in peripheral organs (liver, thymus, adrenal gland) is not developmentally regulated, unlike in the brain.
- In adrenalectomized rats, restraint stress did not activate the PSR in the thymus or liver but did in the hippocampus.
- Dexamethasone successfully induced the PSR in all organs of adrenalectomized rats.
Conclusions:
- Brain PSR is developmentally regulated, aligning with the cessation of the stress hypo-responsive period.
- Peripheral PSR relies on the hypothalamic-pituitary-adrenocortical (HPA) axis and glucocorticoids, not neuronal activation.
- The brain's PSR can be activated by glucocorticoids or neuronal signals independently.
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