Assessment of pancreatic and hepatic function in Yucatan miniature swine exhibiting impaired glucose tolerance.

A group of Yucatan miniature swine exhibiting impaired glucose tolerance (Kq = .91 +/- .04), were examined with respect to their portal and hepatic vein insulin levels following a fasting intravenous glucose tolerance test. The majority of these animals (9 of 11) were found to exhibit the expected portal vein insulin deficiency. This deficiency was found to encompass all phases of the insulin response and was not limited to the acute secretory phase. The remaining two animals were found to have normal portal vein insulin concentrations while exhibiting reduced hepatic vein insulin levels, and impaired glucose tolerance. An excessive rate of hepatic insulin extraction is proposed to explain the etiology of the insulin deficiency and glucose intolerance observed in these latter two animals.