CORRELATION BETWEEN INSULIN SECRETION AND MORPHOLOGICAL APPEARANCE IN 4 PATIENTS WITH INSULINOMA

Abstract

Insulin secretory responses were studied in relation to IRI concentration and electron-microscopic appearance of the tumors in 4 human insulinomas, one of which was of malignant nature. In a case with low basal insulin secretion and exaggerated insulin responses by insulin stimulants, the tumor had high concentration of IRI and typical β granules. In 2 cases with high basal insulin secretion, one case showed high insulin responses and the other case low insulin responses by insulin stimulants. However, in these 2 cases, the tumors contained low concentration of IRI and revealed atypical granules. Meanwhile, an insulinoma, which showed high plasma insulin in the fasting state and failed to respond to various insulin stimulants, demonstrated high concentration of IRI in the tumor and typical β granules.