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document
Pulsatile insulin delivery is more efficient than continuous infusion in modulating islet cell function in normal subjects and patients with type 1 diabetes . The respective modulating effects of continuous and intermittent insulin delivery on pancreatic islet cell function were studied in seven normal men and nine insulin-dependent ( type 1 ) diabetic patients . In the normal men , saline or continuous ( 0.8 mU kg-1 min-1 ) or pulsatile ( 5.2 mU kg-1 min-1 , with a switching on/off length of 2/11 min ) human insulin were delivered on different days and in random order . Despite hyperinsulinemia , blood glucose was kept close to its basal value by the glucose clamp technique . The diabetic patients also were infused in random order and on different days with either saline or a smaller amount of insulin delivered continuously ( 0.15 mU kg-1 min-1 ) or in a pulsatile manner ( 0.97 mU kg-1 min-1 for 2 min , followed by 11 min during which no insulin was infused ) . In all experiments , 5 g arginine were given iv as a bolus dose 30 min before the end of the study , and plasma C-peptide and glucagon levels were determined to assess islet cell function . In the normal men , insulin administration resulted in a significant decline of basal plasma glucagon and C-peptide levels and in a clear-cut decrease in the arginine-induced glucagon response . These effects of insulin were significantly more marked when insulin was delivered in a pulsatile rather than a continuous manner . In the insulin-dependent diabetic patients , the lower dose of insulin infused continuously did not alter the basal or arginine-stimulated glucagon response . In contrast , when the same amount of insulin was delivered intermittently , arginine-induced glucagon release was greatly reduced . Thus , these data support the concept that insulin per se is a potent physiological modulator of islet A- and B-cell function . Furthermore , they suggest that these effects of insulin are reinforced when the hormone is administered in an intermittent manner in an attempt to reproduce the pulsatile physiological release of insulin .
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Intervention_Physical
Pulsatile insulin delivery
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Intervention_Physical
continuous infusion
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Intervention_Physical
continuous and intermittent insulin delivery
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Intervention_Pharmacological
saline
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Intervention_Pharmacological
continuous
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Intervention_Pharmacological
pulsatile
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Intervention_Pharmacological
human insulin
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Intervention_Pharmacological
saline
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Intervention_Physical
smaller amount of insulin delivered continuously
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Intervention_Pharmacological
in a
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Intervention_Physical
pulsatile
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Intervention_Pharmacological
manner
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Intervention_Pharmacological
arginine
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Outcome_Physical
Pulsatile insulin delivery
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Outcome_Physical
plasma C-peptide
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Outcome_Physical
glucagon levels
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Outcome_Physical
basal plasma glucagon
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Outcome_Physical
C-peptide levels
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Outcome_Physical
arginine-induced glucagon response
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Outcome_Physical
basal or arginine-stimulated glucagon response
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Outcome_Physical
arginine-induced glucagon release
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Outcome_Physical
physiological modulator of islet A- and B-cell function
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Outcome_Physical
pulsatile physiological release of insulin
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Participant_Condition
normal subjects and patients with type 1 diabetes .