Hormone status in occupational toluene exposure

Twenty toluene‐exposed rotogravure printers, without signs of solvent‐induced toxic encephalopathy, had lower median plasma levels of follicle stimulating hormone (FSH) (3.2 vs. 4.9 IU/L; p = .02) and luteinizing hormone (LH) (6.4 vs. 7.2 IU/L; p = .05) and also lower serum levels of free testosterone (76.8 vs. 86.8 pmol/L; p = .05), respectively, than 44 unexposed referents. The individual time‐weighted toluene levels in air were 36 (median; range 8–111) ppm. The printers' median toluene levels in blood were 1.7 (1.0–6.6) μmol/1, and in subcutaneous adipose tissue 5.7 (2.5–21) mg/kg fat. There was a negative association between blood toluene and plasma levels of prolactin. In eight printers, the levels of FSH and LH increased during a 4 week vacation, while the levels of thyroid stimulating hormone, free triiodothyronine, and free thyroxine decreased during the same period. The results indicate a slight, reversible efect of toluene on the cortical level or on the hypothalamic‐pituitary axis at exposures well below the permissible levels, possibly mediated through an effect on catecholamine neurotransmission. © 1992 Wiley‐Liss, Inc.