Summary
To examine the possibility that the concentration of circulating proinsulin-like material (PLM) might be helpful in evaluating the therapeutic response of patients with islet cell tumours, serum levels of PLM in three patients with islet cell tumours were correlated with hypoglycaemic symptoms and plasma glucose concentrations before and after treatment. In two patients ranges of fasting PLM concentration were 0.21–0.29 and 0.91–0.93 ng/ml, respectively, before treatment. After surgical excision of their islet cell adenomas, PLM concentrations decreased to 0.06–0.09 and 0.03–0.05 ng/ml. Insulin concentrations were low preoperatively in both patients and were unchanged postoperatively. The resulting relief from hypoglycaemia was paralleled by a reduction of PLM, with no significant change in insulin. In a third patient, treatment with streptozotocin resulted in marked symptomatic improvement, a 65% reduction in PLM concentration, but no significant change in insulin levels. Relapse was associated with increasing frequency of hypoglycaemic symptoms and increasing PLM concentrations. These findings suggest that changes in the levels of serum PLM may prove to be a sensitive indicator of the response of islet cell tumours to therapy.
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Supported by grants RR-51 from the General Clinical Research Centers. Program of the Division of Research Resources and Training Grant. 5 TO1 AM 05101, National Institutes of Health, Veterans Administration Endocrine Training Program TR-202 and USPH AM3941 and Bertha and Henry Brownstein Foundation
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Alsever, R.N., Stjernholm, M.R., Sussman, K.E. et al. Clinical correlations of serum proinsulin-like material in islet cell tumours. Diabetologia 12, 527–530 (1976). https://doi.org/10.1007/BF01219519
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DOI: https://doi.org/10.1007/BF01219519