Increased vasoconstrictor sensitivity to glucocorticoids in essential hypertension

Area of Science:

• Endocrinology
• Cardiovascular Physiology
• Hypertension Research

Background:

• Glucocorticoids are known to elevate blood pressure.
• Essential hypertension was previously thought to be unrelated to glucocorticoids due to normal cortisol levels.
• Emerging evidence suggests increased tissue sensitivity to cortisol may play a role.

Purpose of the Study:

• To investigate whether essential hypertension is associated with increased tissue sensitivity to glucocorticoids.
• To explore the potential mechanisms, including glucocorticoid receptor sensitivity and 11 beta-dehydrogenase activity.

Main Methods:

• Compared dermal vasoconstriction responses to topical cortisol and beclomethasone dipropionate in 11 hypertensive patients and 11 controls.
• Assessed hypothalamic-pituitary glucocorticoid receptor sensitivity using dexamethasone suppression tests.
• Measured 11 beta-dehydrogenase activity by determining the half-life of [11 alpha-3H]cortisol.

Main Results:

• Hypertensive patients exhibited significantly increased dermal vasoconstriction to both cortisol and beclomethasone dipropionate.
• Glucocorticoid receptor sensitivity was normal in hypertensive patients.
• 11 beta-dehydrogenase activity was impaired in essential hypertension, indicated by prolonged cortisol half-lives, but this did not correlate with vasoconstriction response.

Conclusions:

• Vasoconstrictor sensitivity to glucocorticoids is elevated in essential hypertension.
• This increased sensitivity may contribute to the elevated peripheral vascular resistance characteristic of the disease.
• The precise mechanism for this heightened sensitivity requires further investigation, potentially involving genetic factors.