Low- and high-frequency insulin secretion pulses in normal subjects and pancreas transplant recipients: role of extrinsic innervation.
Low-frequency ultradian and high-frequency insulin secretion pulses were studied in normal subjects and in metabolically stable pancreas transplant recipients. Insulin secretion pulsatility was evaluated after deconvoluting the pulsatile plasma C peptide concentrations with its kinetic coefficients. In normal subjects, ultradian insulin secretion pulses with periodicities of 75-115 min were consistently observed during the 24-h secretory cycle. Pulse period and relative amplitude during the overnight rest (95 +/- 4 min and 27.6 +/- 2.4%) were similar to those during the steady state of continuous enteral feeding (93 +/- 5 min and 32.6 +/- 3.3%). Sampling at 2-min intervals revealed the presence of high-frequency insulin secretion pulses with periodicities of 14-20 min and an average amplitude of 46.6 +/- 5.4%. Pancreas transplant recipients had normal fasting and fed insulin secretion rates. Both low- and high-frequency insulin secretion pulses were present. The high-frequency pulse characteristics were identical to normal. Low-frequency ultradian pulse periodicity was normal but pulse amplitude was increased. Thus, ultradian insulin secretory pulsatility is a consistent feature in normal subjects. The low- and high-frequency secretion pulsatilities are generated independent of extrinsic innervation. Autonomic innervation might modulate low-frequency ultradian pulse amplitude exerting a dampening effect.
Sonnenberg
G E
GE
Department of Medicine, Medical College of Wisconsin, Milwaukee 53226.
Hoffmann
R G
RG
Johnson
C P
CP
Kissebah
A H
AH
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000097:blood; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D008297:Male; D016035:Pancreas Transplantation; D010507:Periodicity; D012636:Secretory Rate
D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin