[Mechanism of hypoglycemia in insulinoma]

A study was made of the capacity of insulinoma to catalyze the splitting of hippuryl-L-arginine (HA) and the contents of proinsulin-like component in the tissues of the tumours and in the blood serum of the patients. As revealed, in the absence of HA splitting by the tumour cytoplasmic fraction in the neutral pH zone there was noted a higher proinsulin-like component both in the tumour tissue and in the blood serum. An increase amount of proinsulin-like component in the blood serum stipulates possibly a more prolonged period of starvation before the occurrence of hypoglycemia, and a less pronounced picture of hypoglycemia in such patients in comparison with the patients whose tumours were capable of splitting HA similarly to the normal islands of Langerhans.