Double standards over pound dogs.
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Biomedical subjects
Publications and source records attributed to A Litchfield.
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The study aim was to investigate the role of the parasympathetic nervous system in the control of glucose tolerance in man. Glucose kinetics were determined during an oral glucose tolerance test (OGTT) in six subjects with truncal vagotomies and six control subjects. Basal plasma glucose levels in the two groups were equal; however, 20 to 40 minutes after the OGTT, glucose was higher in vagotomized compared with control subjects (P < .02). There were no differences in insulin levels between the subjects. Glucagon decreased after the OGTT in the controls, whereas in the vagotomized subjects it increased transiently and did not decrease beyond basal levels. There was no difference in basal hepatic glucose production, but suppression was greater in controls in the first 10 minutes (P < .01). Gut-derived glucose appearance increased faster and to a higher level (56.0 +/- 8 v 29.7 +/- 2.9 mumol/kg/min, P < .02) in vagotomized subjects. There were no differences in the metabolic clearance rate of glucose between the two groups. It is concluded that parasympathetic innervation of the pancreas is essential for suppression of glucagon secretion during hyperglycemia. However, abnormal glucose tolerance in vagotomized subjects is primarily due to rapid gut glucose absorption, with the denervated parasympathetic system playing only a minor role.
A transient rise in hepatic glucose production (HGP) after an oral glucosa load has been reported in some insulin-resistant states such as in obese fa/fa Zucker rats. The aim of this study was to determine whether this rise in HGP also occurs in subjects with established non-insulin-dependent diabetes mellitus (NIDDM). Glucose kinetics were measured basally and during a double-label oral glucose tolerance test (OGTT) in 12 NIDDM subjects and 12 non-diabetic 'control' subjects. Twenty minutes after the glucose load, HGP had increased 73% above basal in the NIDDM subjects (7.29 +/- 0.52 to 12.58 +/- 1.86 mumol/kg/min, P < 0.02). A transient rise in glucagon (12 pg/ml above basal, P < 0.004) occurred at a similar time. In contrast, the control subjects showed no rise in HGP or plasma glucagon. HGP began to suppress 40-50 min after the OGTT in both the NIDDM and control subjects. A 27% increase in the rate of gut-derived glucose absorption was also observed in the NIDDM group, which could be the result of increased gut glucose absorption or decreased first pass extraction of glucose by the liver. Therefore, in agreement with data in animal models of NIDDM, a transient rise in HGP partly contributes to the hyperglycemia observed after an oral glucose load in NIDDM subjects.