Modulation of Proinsulin Messenger RNA After Partial Pancreatectomy in Rats Relationships to Glucose Homeostasis

These studies of partial pancreatectomy assess pancreatic proinsulin messenger RNA (mRNA) levels as an index of in vivo insulin biosynthesis, and show relationships to glucose homeostasis. Rats were subjected to sham operation, 50% pancreatectomy (Px), or 90 % Px, and were examined after 1, 3, or 14 wk. Proinsulin mRNA was measured by dot hybrid-ization to complementary DNA. After 50 % Px there was a nearly complete adaptation of proinsulin mRNA. After 90% Px a marked increase of proinsulin mRNA occurred, but it was insufficient and it was not maintained with time. The deficit in insulin production is related to development of hyperglycemia. Sham-operated controls showed no worsening of fasting or fed blood glucose or of intraperitoneal glucose tolerance withi