Measurement of potato steroidal alkaloids in human serum and saliva by radioimmunoassay.

Radioimmunoassay methods are described for measuring potentially toxic potato glycoalkaloids and the aglycone solanidine in human serum and saliva. Solanidine and total alkaloid concentrations in serum and saliva during the summer are given for a group of subjects from the UK and a group from Sweden. Serum concentrations ranged from 3.2 to greater than 125 nmol/l for total alkaloid and 2.5 to 92.5 nmol/l for solanidine and were comparable in the two populations. Salivary total alkaloid concentrations were only about 10% of serum values. Salivary solanidine concentrations did not exceed 20% of the serum levels. Good correlation was found between serum and salivary alkaloid concentrations (r = 0.734, for solanidine; r = 0.892 for total alkaloid). Serum and salivary alkaloid concentrations were significantly raised in a group of Swedish subjects eating potatoes containing unusually high concentrations of alkaloids when compared with those in a group of subjects eating their normal diets.