Higher proinsulin and specific insulin are both associated with a parental history of diabetes in nondiabetic Mexican-American subjects.
Both insulin resistance and decreased insulin secretion have been hypothesized to be precursors of non-insulin-dependent diabetes. An elevated proinsulin concentration reflects abnormal proinsulin processing and could indicate abnormal insulin secretion. We examined fasting insulin (measured by a radioimmunoassay that does not cross-react with proinsulin), as a marker of insulin resistance, and proinsulin and the fasting proinsulin-to-insulin ratio, as markers of impaired proinsulin processing, in 597 nondiabetic Mexican-Americans from the San Antonio Heart Study. Fasting insulin, proinsulin, and the fasting proinsulin-to-insulin ratio were higher in subjects with a parental history of diabetes than in subjects without such a history. These differences remained statistically significant after adjustment for obesity, body fat distribution, and glucose tolerance. A parental history of diabetes in nondiabetic Mexican-Americans is associated with an increase in fasting specific insulin and a disproportionate increase in proinsulin relative to insulin. These data suggest that both increased insulin resistance and abnormal processing of proinsulin are present in offspring of parents with diabetes.
Haffner
S M
SM
Division of Clinical Epidemiology, University of Texas Health Science Center at San Antonio 78284-7873, USA.
Stern
M P
MP
Miettinen
H
H
Gingerich
R
R
Bowsher
R R
RR
D001786:Blood Glucose / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics*; D005215:Fasting; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance; D008297:Male; D017058:Mexican Americans / Q000235:genetics*; D008875:Middle Aged; D009765:Obesity / Q000097:blood; D010290:Parents; D011384:Proinsulin / Q000097:blood*; D012016:Reference Values; D013781:Texas
D001786:Blood Glucose; D007328:Insulin; D011384:Proinsulin