[Thyroid function in smelters after long-term exposure to heavy metals]

In the year 1995 in a group of 93 male workers of a copper smelter (mean age = 40,7 years, exposure time = 8,5 years) following parameters were measured: blood levels of: lead and cadmium; serum levels of copper, zinc, calcium and magnesium-with use of atomic absorption spectrophotometry; FEP-with Piomelli's method; and T3, T4 and TSH in serum with radioimmunometric method. Mean blood lead level was 38,2 micrograms/dl, and concentrations of other metals and hormones were within norm limits. Mean level of FEP was slightly above norm (FEP = 106,5 micrograms/100 ml E). We found no correlation between investigated hormones (T3, T4 and TSH) and age, length of exposure nor blood lead level. We found a significant inverse correlation between FEP and TSH (r = -0,207; p < 0,047). This correlation could point to the fact that lead burden (expressed not in the actual blood level but in the FEP concentration) could negatively influence endocrine functions through hypothalamic-pituitary axis.