Abstract: A method of sensing blood glucose levels in the steps of passing glucose from a peritoneal fluid through a semi-permeable membrane and into a closed chamber, metabolizing the passed glucose in the closed chamber with a yeast suspension to produce a level of carbon dioxide and detection of the level of carbon dioxide, and controlled insulin infusion into blood as a consequence of detected carbon dioxide level. Implantable apparatus is also provided for carrying out the method within a body of live tissue.