Changes in plasma and salivary immunoreactive insulin were studied in saliva and blood of 9 healthy subjects following either oral glucose or a test meal ingestion at 30 min intervals for up to 3h. The levels of plasma immunoreactive insulin reached maximum at 60 min with a value of 62.77 +/- 6.52 microU/ml after the glucose load and 62.62 +/- 6.52 microU/ml after the test meal. In the case of salivary immunoreactive insulin levels, the maximum was attained at 90 min with a value of 18.47 +/- 2.68 microU/min after the glucose load and 22.40 +/- 2.01 microU/min after the test meal. Positive linear correlation (r = 0.74) was found between the salivary and plasma immunoreactive insulin levels.