Aldosterone: Effects and Regulation

by Thad Wilson, PhD

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    How this process is controlled is interesting. Before we go through that, let's also discuss how if you give someone a drug such as aldosterone, what happens to the overall response of sodium, chloride, and potassium. So we have baseline levels and these are urinary excretion rates of sodium. When aldosterone is given, you see a dramatic reduction in the urinary excretion of sodium. If there is a reduction in the urinary excretion that means it's being reabsorbed. Once you remove aldosterone, it recovers. If you look at urinary chloride concentration, if you think about having a nice, stable baseline level, once you give out aldosterone, you again see a decrease in chloride excretion. Then this recovers again. Potassium is interesting in that you have basal levels, but once you give out aldosterone you see a secretion of potassium. So unlike sodium and chloride which are both reabsorbed to a greater degree with aldosterone, potassium is secreted. So let's walk through the mechanism by which how aldosterone does this particular action. The first thing to think about is where aldosterone comes from. Aldosterone is part of the renin angiotensin aldosterone system and it responds to low blood pressure than blood volumes which result in low renal blood flows which increases renin, angiotensin I, angiotensin II is increased and then that will increase aldosterone levels. The second mechanism by which aldosterone can increase is by having high levels of potassium, so if you're hyperkalemic. So either angiotensin II or hyperkalemia both will stimulate the aldosterone release. What does the aldosterone do at the level of the kidney? Aldosterone is a steroid hormone. So aldosterone can move through the basal lateral membrane because it's lipophilic. It binds to a cytosolic receptor known as mineralocorticoid receptor. This particular receptor once bound to aldosterone...

    About the Lecture

    The lecture Aldosterone: Effects and Regulation by Thad Wilson, PhD is from the course Renal Physiology.

    Included Quiz Questions

    1. Potassium
    2. Sodium
    3. Chloride
    4. Calcium
    1. Inner medullary collecting duct
    2. Thin descending limb of the loop of Henle
    3. Thin ascending limb of the loop of Henle
    4. Distal convoluted tubule
    1. Sodium and Chloride
    2. Sodium and Glucose
    3. Sodium and Potassium
    4. Potassium and chloride
    5. Sodium and calcium

    Author of lecture Aldosterone: Effects and Regulation

     Thad Wilson, PhD

    Thad Wilson, PhD

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