PROTEIN-BOUND PYRROLES IN RAT HAIR FOLLOWING SUBCHRONIC INTRAPERITONEAL INJECTIONS OF 2,5-HEXANEDIONE

Studies were initiated to ascertain whether body hair could be used to develop a biological marker for chronic exposure to industrial neurot oxicants that yield the metabolite 2,5-hexanedione (2,5-HD), that is, n-hexane and methyl n-butyl ketone. Rats were injected daily with a 50 mg/kg ip dose of 2,5-HD for 45 d. At intervals, body hair and individ ual vibrissae were removed (under general anesthesia) and tested for t he presence of pyrrole substances with p-N,N-dimelhylaminobenzaldehyde (DMAB, Ehrlich's reagent). Vibrissae and body hair were stained a red dish color that was distinctly different from that observed with the h air taken from control animals. Solubilized body hair protein from the treated animals gave a positive Ehrlich's test, while that from contr ol animals was negative. Spectral analysis of the DMAB-treated hair fr om experimental animals disclosed a maximum absorbance at 530 nm, whic h indicated the presence of pyrrole substituents. Serial analysis of i ndividual nose hairs taken during 2,5-HD administration showed a progr ession with time of the region staining positively for pyrroles, thus indicating that the process can proceed in growing hair. These finding s suggest the potential utility of hair as an indicator for chronic ex posure to this class of industrial chemicals possessing neurotoxicity potential. This could complement urinary analysis, which is now used t o confirm recent exposure.