[Sis290025]

Exactly how is insulin secretion from pancreatic beta cells governed or tied in to blood glucose concentrations?

Thank you.

[Yggdrasil]

http://en.wikipedia.org/wiki/Insulin#Regulatory_action_on_blood_glucose

In short, high blood glucose levels trigger the secretion of insulin.  Also (not mentioned in the wikipedia article), low blood glucose levels trigger the secretion of another hormone, glucagon (http://en.wikipedia.org/wiki/Glucagon), which acts to counteract the low blood glucose levels by releasing more glucose into the blood.

A more reliable, better organized, and more thorough discussion of the subject can be found in any biochemistry text.