Renal functional response to the mushroom poison gyromitrin.

The poison gyromitrin, found in the edible false morel Gyromitra esculenta Fr. ex Pers., caused in rats an increased diuresis in which urine was produced with a weak alkaline pH, a high excretion of sodium (530%), and potassium (210%). The observed increase lasted for about 12 h and was followed by a rentention with regard to the volume and the Na-excretion for about 72 h. On the basis of [3H] inulin excretion an increased glomerular filtration was determined followed by a decrease 12 h after application of gyromitrin. An increase of creatinine and urea in the serum could not be established during the retention phase. The diuresis as well as the excretion of sodium could be antagonized by injection of an equimolar dose of pyridoxine. The hydrazine derivative N-methyl-N-formylhydrazine (MFH), which is formed rapidly from gyromitrin by hydrolysis, was without any effect on the renal function. In order to explain the effectiveness of the relatively lipophilic gyromitrin, the non-effectiveness of the more hydrophilic hydrazine MFH and the blockade of the gyromitrin effect by pyridoxine, a mechanism involving the central nervous system is discussed.