Endocrine function in mercury exposed chloralkali workers

Area of Science:

• Endocrinology
• Occupational Health
• Toxicology

Background:

• Occupational exposure to mercury (Hg) vapor is a concern in industries like chloralkali production.
• The potential for Hg accumulation in endocrine glands and subsequent functional impairment requires investigation.

Purpose of the Study:

• To assess the functional impact of occupational mercury vapor exposure on the pituitary, thyroid, testes, and adrenal glands.
• To determine if mercury accumulation in these glands leads to endocrine dysfunction.

Main Methods:

• Measured serum hormone levels (TSH, prolactin, free T4, free T3, testosterone) and urinary cortisol in 41 chloralkali workers and 41 controls.
• Assessed mercury levels in urine (U-Hg) and blood (B-Hg) to quantify exposure.

Main Results:

• Significantly higher free thyroxine (free T4) and a higher free T4/free T3 ratio were observed in highly exposed workers.
• Free triiodothyronine (free T3) showed an inverse association with cumulative Hg exposure, suggesting inhibited T4 to T3 conversion.
• Total testosterone correlated positively with cumulative Hg exposure, but free testosterone did not.

Conclusions:

• Mercury vapor exposure may inhibit the 5'-deiodinase enzyme, affecting the conversion of thyroxine to triiodothyronine.
• The studied endocrine functions appear unaffected by mercury vapor at the exposure levels in this study, apart from the T4 to T3 conversion.
• Growth hormone secretion was not evaluated in this study.