Reduced serum carnosinase activity in hypothyroidism.

Area of Science:

• Biochemistry
• Endocrinology
• Neurology

Background:

• Carnosinase enzyme hydrolyzes carnosine in muscle.
• Carnosinase deficiency is linked to neuromuscular abnormalities.
• Thyroid dysfunction frequently impacts neuromuscular systems.

Purpose of the Study:

• To investigate serum carnosinase activity in patients with thyroid dysfunction.
• To explore the relationship between carnosinase activity and thyroid hormones.
• To assess the clinical relevance in diagnosing carnosinase deficiency disorders.

Main Methods:

• Serum carnosinase activity was measured in hyperthyroid, hypothyroid patients, and normal subjects.
• Activity levels were compared across groups.
• Correlations with serum thyroxine and creatine kinase were analyzed.

Main Results:

• Serum carnosinase activity was not significantly different in hyperthyroidism compared to controls.
• Hypothyroidism showed significantly lower carnosinase activity than normal subjects.
• In five hypothyroid patients, carnosinase activity normalized after hormone replacement therapy.
• Carnosinase activity correlated positively with thyroxine and negatively with creatine kinase in hypothyroidism.

Conclusions:

• Serum carnosinase activity is reduced in hypothyroidism.
• Carnosinase activity normalization post-therapy supports the link with thyroid function.
• This measurement could be valuable for differential diagnosis of carnosinase deficiency.