Can some molec. biologists or doctors point me to some info on stimulating EPO produc

Factual Questions
1

Okay, so the title is really awkward, but basically what I’m looking for is some detailed information on how the production of EPO (erythropoietin) is actually stimulated naturally.

So obviously I know that both altitude and exercise will stimulate EPO and eventually RBC’s and hematocrit, but I’m curious as to the exact mechanism.

Is it a decrease in oxygen saturation that actually stimulates your kidneys to produce EPO? Or is some other signaling mechanism at work which makes your body say to itself, “yo, high altitude, suckas’?” Blood pH?

Assuming that it’s oxygen saturation which leads to EPO stimulation, does anyone have any ideas as to what type of pulse-ox’s will effectively lead to EPO stimulation? Furthermore, what exactly is considered an, “unhealthy” pulse-ox in healthy individuals, as in it causes altered mentation or other health issues, in otherwise healthy people?

Cites would be awesome, but general infomation that you just know to be true is also appreciated of course.

2

There’s some other signalling mechanism, possibly involving adenosine, but no one seems to have nailed it down yet.

You might find what you want through these searches:
erythropoietin production hypoxia
erythropoietin production hypoxia adenosine
erythropoietin production hypoxia adenosine review (Google Scholar)

A couple interesting hits:
Enhanced erythropoietin production by calcium entry blockers in rats exposed to hypoxia
Erythropoietin production in healthy volunteers subjected to controlled hypobaric hypoxia: further evidence against a role for adenosine.