An investigation of potato alkaloid levels in the normal population and their relationship to foetal neural tube defects.

Radioimmunoassay methods were developed for the measurement of solanidine and total alkaloid in serum, urine and saliva. Solanidine and total alkaloid concentrations were measured in a group of normal pregnant women and a group of women pregnant with a foetus subsequently shown to be affected by a neural tube defect (NTD). Serum alkaloid concentrations were, contrary to expectations, lower in the NTD group, casting doubt on the theory suggesting a link between potato alkaloids and NTD serum zinc and folate concentrations were also measured in the two groups and no significant differences were noted. Solanidine and total alkaloid concentrations were measured in the serum, urine and saliva of healthy volunteers and reference ranges established. Total alkaloid concentrations were higher than solanidine in serum and urine but similar in saliva, indicating solanidine as the predominant salivary alkaloid. Alkaloid concentrations measured in a case of potato poisoning and in subjects on high alkaloid intake had serum, urine and salivary solanidine and total alkaloid concentrations much greater than the reference ranges. A pharmacokinetic study was carried out to obtain body fluid alkaloid concentrations following a potato load. The glycosides were found to be rapidly absorbed before metabolism to solanidine, urinary excretion accounted for a very small percentage of the total dose. Affinity chromatography allowed concentration of potato alkaloids in urine and serum for qualitative analysis of metabolites. A high performance liquid chromatography (HPLC) method was developed and used in conjunction with thin layer chromatography (TLC) to separate the principle alkaloids found in urine and serum. As well as the glycosides, a-solanine and a-chaconine, the presence of the aglycone solanidine was established. Additionally, several of the lower glycosides were found in serum and urine