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Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pharmacological doses of 24R,25-dihydroxyvitamin D3 (24,25D3) inhibited both phasic and tonic contraction of Sprague-Dawley (SD) rat tail artery helical strips induced by KCl, norepinephrine (NE), and arginine vasopressin (AVP) in organ-bath studies. 24,25D3 also decreased the tension dependent on external calcium influx induced by KCl, AVP, and NE and the tension dependent on internal calcium release from intracellular calcium stores induced by NE. In vascular smooth muscle cells isolated from SD rat tail artery, 24,25D3 reduced membrane L-type calcium channel current and the increment of intracellular calcium concentration induced by KCl. It is suggested that 24,25D3 directly relaxed precontracted SD rat-tail artery by its inhibitory effect on plasma membrane and intracellular organelle calcium channels.
Steroids 1996 Nov
PMID:Inhibition of membrane L-type calcium channel activity and intracellular calcium concentration by 24R, 25-dihydroxyvitamin D3 in vascular smooth muscle. 891 61

Steroid, amine and peptide hormones affect the peripheral vestibular system. Vasopressin hypersensitivity of the endolymphatic sac may be implicated in the pathogenesis of Meniere's disease. Specific vasopressin antagonists will help define the role of vasopressin in Meniere's disease. The modulation of central vestibular pathways by neuroactive steroids may involve effects on gamma-aminobutyric acid-ergic and glutaminergic pathways. The vestibular nuclei also express enzymes that are important in the synthesis of steroids and the modulation of their activity. Steroids mediate both facilitatory and deleterious effects of stress on vestibular compensation. The quality and quantity of stressor that determines the pattern of hormonal output, may be important. Clinical observation suggests that episodic ataxia type 2, a P/Q calcium channelopathy, may be phenotypically modulated by endocrine fluctuations. Steroid hormones may affect the episodic ataxia type 2 phenotype by modulation of voltage-gated calcium channel activity via second messenger systems and ion channel subunit expression. Despite evidence to support the link, the role of the endocrine system in vestibular function and disease is as yet virtually unexplored.
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PMID:The endocrine system, vertigo and balance. 1117 14

Recent studies provide evidence that aldosterone (Aldo) accelerates hypertension, proteinuria and glomerulosclerosis in animal models of chronic renal failure. Although the underlying mechanisms are not well defined, Aldo may exert these deleterious renal effects by elevating renal vascular resistance (RVR) and glomerular capillary pressure (P(GC)). To test this possibility, we studied the action of Aldo on rabbit afferent (Af-) and efferent arterioles (Ef-Arts), crucial vascular segments to the control of glomerular hemodynamics. Aldo caused rapid (within 5 min) constriction in both arterioles. The constriction was not affected by spironolactone but was reproduced by membrane-impermeable albumin-conjugated Aldo, suggesting that vasoconstrictor actions are non-genomic. This notion was further supported by the finding that neither actinomycin D nor cycloheximide had effect. The vasoconstrictor action of Aldo on Af-Arts was inhibited by nifedipine (L-type calcium channel blocker), whereas that on Ef-Arts was inhibited by efonidipine (both L- and T-type calcium channel blocker) but not nifedipine. Disrupting the endothelium or nitric oxide (NO) synthesis inhibition augmented the vasoconstriction in Af-Arts, demonstrating that endothelium-derived NO modulates the vasoconstrictor actions of Aldo. Thus, Aldo causes non-genomic vasoconstriction via calcium mobilization thorough L- or T-type calcium channels in Af- or Ef-Arts, respectively. These vasoconstrictor actions on the glomerular microcirculation may play an important role in the pathophysiology and progression of renal diseases by elevating RVR and P(GC), especially when endothelium functions are impaired. In addition to our study, this review describes recent findings on the rapid cardiovascular actions of Aldo, with a particular attention to the renal hemodynamics.
Steroids 2006 Apr
PMID:Aldosterone and the kidney: rapid regulation of renal microcirculation. 1628 72