Tumor and serum levels of proinsulin and insulin in insulinoma patients.
The amounts of immunoreactive proinsulin (IRP), immunoreactive insulin (IRI), and C-peptidelike immunoreactivity (CPR) in six insulinomas and one nesidioblastosis lesion were determined together with those in the surrounding pancreatic tissue. Four non-insulinoma and nondiabetic human pancreases were used as the control. The IRP in the seven tumors ranged from 5.85 micrograms/g to 65.45 micrograms/g (mean +/- SEM, 28.70 +/- 8.01 micrograms/g), while the IRP in the surrounding pancreatic tissue ranged from 2.08 micrograms/g to 11.71 micrograms/g (5.32 +/- 1.76 micrograms/g). Control pancreases had an IRP content of 12.01 +/- 2.36 micrograms/g. The IRI in the seven tumors ranged from 4.02 U/g to 47.97 U/g (14.40 +/- 6.35 U/g), while that in the surrounding pancreatic tissue ranged from 0.28 U/g to 3.64 U/g (2.32 +/- 0.63 U/g). Mean tumor CPR was 206.84 +/- 81.6 micrograms/g and it was 29.16 +/- 9.15 micrograms/g in the surrounding pancreatic tissue. The molar ratio of the IRP to IRI content was 6.83 +/- 1.95% for tumor tissue and 6.24 +/- 2.18% for the surrounding pancreatic tissue. These levels were similar to the ratio in the control pancreases (7.67 +/- 1.88%), in contrast to the higher serum IRP/IRI ratio in the tumor patients.
Tasaka
Y
Y
Tokyo Women's Medical College, Diabetes Center, Japan.
Nakaya
F
F
Matsumoto
H
H
Odagiri
R
R
Ohgawara
H
H
Omori
Y
Y
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002096:C-Peptide / Q000097:blood / Q000378:metabolism; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D007340:Insulinoma / Q000097:blood / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000378:metabolism; D010182:Pancreatic Diseases / Q000378:metabolism; D010190:Pancreatic Neoplasms / Q000097:blood / Q000378:metabolism*; D011384:Proinsulin / Q000097:blood / Q000378:metabolism*
D002096:C-Peptide; D007328:Insulin; D011384:Proinsulin