Recently, major resection of the pancreas has been carrier out not only to treat
pancreatic carcinoma but also for benign
pancreatic diseases. Dragstedt reported that the amount of
insulin required to control
glycosuria after partial
pancreatectomy is much greater than that needed after total
pancreatectomy. Although it is thought that diabetes after partial
pancreatectomy is considerably different from that after total
pancreatectomy, these pathophysiological changes have not been investigated in detail. In the present experiment, changes in
carbohydrate and
insulin metabolism and
glucagon secretion were studied in dogs in order to elucidate the pathophysiology in diabetes after major resection of the pancreas. Immediately after resection of 90% or more of the entire pancreas, diabetes occurred with absolute
insulin deficiency, being accompanied by decreased function of the anti-
insulin system with poor secretion of
glucagon and delayed recovery of
blood sugar after the
insulin load. Moreover, the half-life of
insulin in this group was much longer than that in normal dogs and close to that after total
pancreatectomy. These results could explain that the dosage of
insulin required to control
blood sugar after resection of 90% or more of the entire pancreas was close to that after total
pancreatectomy. Six weeks or more after resection of 70 to 90% of the entire pancreas, so-called Sandmeyer's diabetes gradually as a consequence of a decrease in insulin secretion and an increase in
glucagon secretion from the remnant pancreas. After the
insulin load,
glucagon secretion markedly increased and recovery of
blood sugar from the
insulin hypoglycemia was good, showing hyperfunction of the anti-
insulin system. Moreover, the half-life of
insulin gradually lengthened but was still shorter than that after total
pancreatectomy. These results could well explain the fact that the
insulin dosage required to control
blood sugar in Sandmeyer's diabetes was 3 to 4 times more than that needed after total
pancreatectomy. After resection of less than 70% of the entire pancreas, diabetes did not occur throughout a period of post-operative observation of up to 66 weeks. After the
insulin load,
glucagon secretion and recovery rate of
blood sugar from the
insulin hypoglycemia were maintained well, showing normal function of the anti-
insulin system, and the half-life of
insulin was also within the normal range.