Hormone causing reabsorption of glucose...

Coldie

Can anybody tell me what the hormone that causes the reabsorption of glucose in the nephrons is?

Thanks.

Coldie

The reabsorption of glucose in the proximal tubule of the nephrons! Come on, SOMEone must know this!

hypatia

I know of two. I don't know which one helps that process.

Antidiuretic Hormone (ADH), produced by the pituitary gland.
Aldosterone, produced by the adrenal cortex.

Coldie

We're familiar with those two. ADH causes the reabsorption of water to increase, and Aldosterone just causes an increase in the reabsorption of Na+ and the excretion of K+. To my understanding, neither of these do anything concerning the reabsorption of glucose. That's why this was such a challenge. I've been unable to find anything on it yet, which is why I made thsi thread.

adrenaline

My memory is vague but I believe there is no hormonal effect.

100% of the glucose is absorbed in the proximal tubule of the nephron where very little hormonal effects are felt. That I know.

The glucose is absorbed via a facilitated transport system where the potential energy of the sodium ion is somehow used to go against the glucose concentration gradient. We also called it contransport and its mechanism is not fully known. (At least my vague reccollection of it). I think it appears that the affinity for the "carrier" for glucose in the epithelium is somehow enhanced by the attachment of the Na+ to that carrier. That's all I know, and I'm not sure if it answers your question.

Coldie

That sounds good, and I'll approach my Bio teacher with that answer, but he did ask us for the hormone that caused it.

DocToxyn

I have to agree with Adrenaline, that there is no direct hormonal control of the reabsorption of glucose in the proximal tubule. It's driven by an active transport process using a sodium/glucose symporter (as mentioned by Adrenaline) the carries in glucose by the co-transport of sodium down its concentration gradient. This gradient is maintained by a Na+-K+ ATPase which consumes ATP to pump out sodium and bring in potassium. This gradient is used to drive numerous processes throughout the body, especially in neurons. Now it could be argued that the sodium is controlled by hormones such as those listed at the bottom of this page and thus anything downstream of this is thus controlled by said hormones, but I would have to say that the question as you stated it is probably not directly mediated by a hormone.

Coldie

Thanks! I'll e-mail him with that and see what he says about it.

Coldie

Thanks for the bonus mark on the test, guys!:D

The answer he was looking for was cortisol, but your explanations were infallable. Thanks again!

Moonbear

How was he reasoning cortisol? I know of no evidence for that being a function of cortisol.