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cortisol - recall
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03-18-2007, 10:48 AM
dr recall was taking cortisol for experiment ..has observed his GFR after steriod therapy
A no change B incresd C decresed D first increse then decrese
03-18-2007, 01:20 PM
steroids will inhibit phospholipase A2--> which will in turn decrease prodaction of PGE2 PGE2 is potent vasodilator of efferent--- missing it will cause vasocnstriction of efferent arteriole which in turn will increase GFR
03-18-2007, 01:31 PM
MAINTENANCE OF NORMAL renal blood flow (RBF) and glomerular filtration rate (GFR) depends on the actions of glucocorticoid hormones. Exact mechanism how GFR is increased is not known but few theories that describe this effect are........
Excess secretion of glucocorticoids causes renal vasodilatation and an increase in GFR,glucocorticoid-induced increases in glomerular plasma flow depend on reductions in both afferent and efferent arteriolar resistances ,the endothelium-derived relaxing factor nitric oxide plays a role in this response There is evidence that other locally released factors such as prostaglandins can act in concert with nitric oxide to cause vasodilatation , but whether prostaglandins play a role in glucocorticoid-induced renal vasodilatation has not been determined. Studies in rats have shown that intrarenal administration of prostaglandin E2 causes renal vasodilatation. Another mechanism that could contribute to glucocorticoid-induced renal vasodilatation is a reduction in the vascular responsiveness to endogenous angiotensin. It is well established that angiotensin plays a major role in the regulation of renal hemodynamics, and it has been shown that acute administration of glucocorticoids reduces the vasoconstrictor activity of angiotensin . Although it has been demonstrated that intravenous administration of glucocorticoids increases systemic vascular responsiveness to vasoconstrictor agents, including angiotensin this probably reflects actions at nonrenal sites, because the kidney is the only vascular bed that vasodilates in response to intravenous infusion of cortisol. |
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