gamma-Glutamyl transpeptidase levels in thyroid disease

Area of Science:

• Biochemistry
• Endocrinology
• Clinical Chemistry

Background:

• Thyroid hormones significantly influence metabolic processes.
• Gamma-glutamyl transpeptidase (GGT) is an enzyme involved in various metabolic pathways.
• The relationship between GGT activity and thyroid dysfunction requires further elucidation.

Purpose of the Study:

• To investigate the association between serum GGT activity and thyroid function.
• To compare GGT levels in hyperthyroid, hypothyroid, and euthyroid individuals.
• To assess the impact of thyroid treatment on serum GGT levels.

Main Methods:

• Measurement of serum GGT, alkaline phosphatase, free thyroxine index (FT4I), free triiodothyronine index (FT3I), and thyrotropin (TSH).
• Analysis of these markers in patients with hyperthyroidism, hypothyroidism, and normal controls.
• Monitoring of GGT levels before and after treatment (radioactive iodine or levothyroxine sodium).

Main Results:

• Elevated serum GGT activity was observed in 10 of 16 hyperthyroid patients.
• No significant difference in FT4I or FT3I between high and normal GGT groups in hyperthyroid patients.
• Serum GGT levels decreased after radioactive iodine treatment for hyperthyroidism and were decreased in hypothyroidism, correlating with TSH levels.
• Levothyroxine sodium replacement therapy in hypothyroid patients led to an increase in serum GGT levels.

Conclusions:

• Serum GGT activity is frequently elevated in hyperthyroidism and decreased in hypothyroidism.
• Thyroid status influences serum GGT levels.
• Achieving euthyroidism restores normal serum GGT levels, suggesting GGT as a potential biochemical marker for thyroid function.