Effect of diphenylhydantoin on patterns of insulin secretion in obese subjects.

The effect of short-term treatment with diphenylhydantoin (DPH) on the insulin secretion patterns during OGTT and on the daily insulin profile was studied in obese patients. DPH treatment for 3 days with a dose of 300 mg/die (100 mg, 3 times daily) significantly decreased the insulin release after glucose ingestion, but did not alter the basal insulin level. No effect on the fasting glucose concentration as well as on the glucose profiles during OGTT was observed after short-term DPH treatment. A smaller decrease of plasma free fatty acid concentration during OGTT performed after DPH administration confirmed the inhibitory effect of the drug on insulin release. Short-term DPH treatment was also shown to decrease markedly the postpradial insulin release in obese patients. No difference was noted between plasma 11-OHCS and serum HGH concentrations during OGTT before and after DPH treatment. The possible therapeutic role of DPH in obesity is discussed.