Difference between ADH and Aldosterone?

[Oscerot]

Hey guys,

I have an upcoming Bio test tomorrow, and I NEED to ACE it. Anyways, upon studying, I ran into a problem.

ADH (Anti-diuretic hormone) helps maintain water balance in the blood by making the membranes of the distal tubule and collecting ducts in the nephron of kidneys more permeable to water. The osmotic pressure makes most of the remaining 15% of water absorbed by the nephron be absorbed into the renal cortex which is absorbed into the blood by the peritubular capillaries. This makes the blood retain most the of water.

Aldosterone helps regulate blood volume and therein blood pressure. It does so basically by the same means as ADH. It makes the distal tubule and collecting duct membrane more permeable to Na+, which creates osmotic pressure and therein more water is reabsorbed into the blood.

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So, what is the difference? It's basically the same thing. It makes sense that when ADH needs to be released, Aldosterone is also released, and vice-versa since they do the same thing.

[sdekivit]

ADH regulates water resorption in the collecting ducts

Aldosteron regulates sodium resorption (and thus indirectly water resorption) in the renal tubules.

--> the effect is the same, but the mechanism iof regulation is different.

[Oscerot]

Test over.

Horrible.

Thanks a lot though.

[Darwinz]

Thanks for this posting about ADH & Aldosterone, had been reading after my lab today. I got the answer for a question I had in my physio class.

[MrMistery]

the molecular basis of the two hormones is also quite different. ADH induces the fusion of intracellular vesicles carrying acquaporins with the PM, increasing the water that can be transported through the membrane. Aldosterone is a steroid, so what it does is to interact with a nuclear receptor that eventually turns on the transcription of a gene encoding a Sodium channel.