Thyroid hormone changes in males exposed to lead in the Buenos Aires area (Argentina).

The relationship between lead levels in blood (PbB) and hormones T3, T4, T4F and TSH were studied in 75 subjects exposed to lead at work. PbB levels in blood were determined by atomic absorption spectrophotometry and hormones by enzymoimmunoassay. Positive and significant correlations among thyroid hormones and TSH vs blood lead level in the ranges 8-50 and 26-50 micro g dl(-1)were found ('r' between 0.304 and 0.621 and 0.431 and 0.619, respectively). At PbB levels between 8 and 26 micro g dl(-1)significant correlation was only found for TSH (r= 0.731). In the range PbB 50-98 micro g dl(-1), 'r' was significant only for T3 (-0.746) and T4 (-0.514). Significant differences were observed in T4 and T4F levels between exposed and non-exposed groups. The results obtained indicate the need for monitoring thyroid hormones and TSH levels in workers exposed to lead.