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Hypertension. 2016 May;67(5):1029-37. doi: 10.1161/HYPERTENSIONAHA.115.06977. Epub 2016 Mar 7.

Glucocorticoids Induce Nondipping Blood Pressure by Activating the Thiazide-Sensitive Cotransporter.

Author information

1
From the The British Heart Foundation Centre for Cardiovascular Science (J.R.I., W.O., T.S.P., A.R.H., R.W.H., N.D., D.J.W., J.W.D., M.A.B.) and The Centre for Integrative Physiology (P.W.F.), The University of Edinburgh, Edinburgh, United Kingdom; and Dietetics, Nutrition, and Biological Sciences Department, Queen Margaret University, Musselburgh, United Kingdom (E.A.S.A.-D.).
2
From the The British Heart Foundation Centre for Cardiovascular Science (J.R.I., W.O., T.S.P., A.R.H., R.W.H., N.D., D.J.W., J.W.D., M.A.B.) and The Centre for Integrative Physiology (P.W.F.), The University of Edinburgh, Edinburgh, United Kingdom; and Dietetics, Nutrition, and Biological Sciences Department, Queen Margaret University, Musselburgh, United Kingdom (E.A.S.A.-D.). Matthew.Bailey@ed.ac.uk.

Erratum in

Abstract

Blood pressure (BP) normally dips during sleep, and nondipping increases cardiovascular risk. Hydrochlorothiazide restores the dipping BP profile in nondipping patients, suggesting that the NaCl cotransporter, NCC, is an important determinant of daily BP variation. NCC activity in cells is regulated by the circadian transcription factor per1. In vivo, circadian genes are entrained via the hypothalamic-pituitary-adrenal axis. Here, we test whether abnormalities in the day:night variation of circulating glucocorticoid influence NCC activity and BP control. C57BL6/J mice were culled at the peak (1:00 AM) and trough (1:00 PM) of BP. We found no day:night variation in NCC mRNA or protein but NCC phosphorylation on threonine(53) (pNCC), required for NCC activation, was higher when mice were awake, as was excretion of NCC in urinary exosomes. Peak NCC activity correlated with peak expression of per2 and bmal1 (clock genes) and sgk1 and tsc22d3 (glucocorticoid-responsive kinases). Adrenalectomy reduced NCC abundance and blunted the daily variation in pNCC levels without affecting variation in clock gene transcription. Chronic corticosterone infusion increased bmal1, per1, sgk1, and tsc22d3 expression during the inactive phase. Inactive phase pNCC was also elevated by corticosterone, and a nondipping BP profile was induced. Hydrochlorothiazide restored rhythmicity of BP in corticosterone-treated mice without affecting BP in controls. Glucocorticoids influence the day:night variation in NCC activity via kinases that control phosphorylation. Abnormal glucocorticoid rhythms impair NCC and induce nondipping. Night-time dosing of thiazides may be particularly beneficial in patients with modest glucocorticoid excess.

KEYWORDS:

cardiovascular disease; circadian rhythm; diabetes mellitus; hypertension; risk factors

PMID:
26953322
PMCID:
PMC4905621
DOI:
10.1161/HYPERTENSIONAHA.115.06977
[Indexed for MEDLINE]
Free PMC Article

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