Gluconeogenesis consumes oxaloacetate, which is essential for the entry of Acetyl CoA into the Krebs cycle.    From Wordnik.com.  [Low-carbers beware the breathalyzer | The Blog of Michael R. Eades, M.D.] Reference

Upon more thinking, oxaloacetate is also a precursor to glucose.    From Wordnik.com.  [Low-carbers beware the breathalyzer | The Blog of Michael R. Eades, M.D.] Reference

Only when the body is sated with glucose will the oxaloacetate then be used by the kreb cycle= end of ketosis.    From Wordnik.com.  [Low-carbers beware the breathalyzer | The Blog of Michael R. Eades, M.D.] Reference

When supplies of oxaloacetate are low, the liver converts the increasing levels of Acetyl CoA into ketone bodies.    From Wordnik.com.  [Low-carbers beware the breathalyzer | The Blog of Michael R. Eades, M.D.] Reference

Activities enzymes concerned pyruvate oxaloacetate metabolism heart liver developing sheep.    From Wordnik.com.  [xml's Blinklist.com] Reference

The data imply that PEPC is critically involved in replenishing the oxaloacetate pool in the citrate cycle under virulence conditions.    From Wordnik.com.  [Journal of Biological Chemistry current issue] Reference

So, if sugar is plentiful, the liver doesn’t need oxaloacetate so it let’s the Acetyl CoA into the Krebs cycle allowing it to ultimately be completely converted to carbon dioxide and water.    From Wordnik.com.  [Low-carbers beware the breathalyzer | The Blog of Michael R. Eades, M.D.] Reference

My understanding (and your GREAT elucidations on a lot of medical explanations-thank you) is that Acetyl CoA will enter the mitochondria (kreb cycle) if and only if oxaloacetate (made directly from some amino acids and indirectly thru glycerol,some a.a.’s and glucose via pyruvate ) is present.    From Wordnik.com.  [Low-carbers beware the breathalyzer | The Blog of Michael R. Eades, M.D.] Reference

Citrate oxaloacetate-lyase.    From Wordnik.com.  [PLoS ONE Alerts: New Articles] Reference