Portal vein insulin flux and arterial glucose fluctuations in response to an oral meal test in islet cell-transplanted dogs.
Insulin flux was determined in the portal vein and simultaneously arterial blood glucose was measured before and during an oral glucose meal in conscious normal and pancreatic islet cell-autotransplanted dogs to test their insulinogenic reserve. These dogs had previously been chronically instrumented with blood flow probes on the portal vein and carotid artery, and blood sampling catheters in the portal vein, hepatic vein, carotid artery, and right external jugular vein. Such a model permits quantitative portal-peripheral comparisons and assessment of hepatic extraction. Sixteen dogs, 10 normal (N) and six long-term (2 months to 2 yrs) islet cell-transplanted dogs (IT) were fed an oral glucose meal as a test (OMT). Baseline portal vein insulin fluxes (PVF) were similar in both groups (25.6 +/- 0.04 pmol/min in N and 24.7 +/- 19.4 pmol/min in IT). Immediately after OMT, PVF rose to 248.2 +/- 40.9 pmol/min in N, but only to 55.9 +/- 17.9 pmol/min in IT. After 30 min PVF peaked for the second time in N at 156 +/- 35.9 pmol/min, declining slowly to baseline after 3 h. In IT, a similar peak at 30 min was seen (143.7 +/- 22.1 pmol/min), declining to a value not different from baseline after 3 h. However, cumulative insulin PV fluxes in the two groups over 3 h were not different. Differences were also seen in postprandial glucose fluctuations, which reached a maximum excursion of 11.8 +/- 0.45 mM in IT, while never rising above 7.8 +/- 0.33 mM in N. After 3 h both groups had similar glucose values.(ABSTRACT TRUNCATED AT 250 WORDS)
O'Brien
D W
DW
Muttart Diabetes Research and Training Centre, University of Alberta, Edmonton, Canada.
Molnar
G D
GD
O'Brien
D C
DC
Rajotte
R V
RV
D000818:Animals; D001158:Arteries; D001786:Blood Glucose / Q000378:metabolism*; D004285:Dogs; D005951:Glucose Tolerance Test; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D016381:Islets of Langerhans Transplantation / Q000502:physiology*; D011169:Portal Vein; D014182:Transplantation, Autologous
D001786:Blood Glucose; D007328:Insulin