The Physiological Effects of Excitatory Amino Acid Neurotransmitters as A Clinical Probe to Evaluate Thyroid Stimulating Hormone as Well as Thyroid Hormones Production

Objective: To evaluate how peripheral glutamate injection affects human thyroid stimulating hormone and thyroid hormones production. Methodology: In 2023, an exploratory inquiry was carried out from October 6 to December 30. Adult healthy men were randomly assigned to receive intravenous Monosodium Glutamate dosages of 0, 5, 10, or 20 mg/kg BW (n = 4 per dose). For one hour before and three hours after the injection of MSG, sequential blood samples were obtained at 30-minute intervals. Serum concentrations of thyroxine (T4), triiodothyronine (T3), and thyroid stimulating hormone (TSH) were assessed using specific enzyme immunoassays (EIA) or immunoenzymatic assays (IEMA). The effectiveness of MSG was evaluated by comparing the mean hormone concentrations measured before and after the pharmaceutical delivery timings using a t-test. Results: With the exception of the 0 mg dose, all MSG dosages raised the serum TSH values (P < 0.05-0.005). Serum T4 concentrations were only shown to increase (P < 0.05) at the highest dose of MSG (20 mg). The mean blood T3 levels significantly decreased (P < (1.01-0.005)) following injections of 0 mg, 5 mg, and 10 mg dosages of MSG. However, after receiving a 20 mg dosage of MSG by injection, no similar drop in T3 levels was seen. Conclusion: For the first time, the current findings show that in case of adult males, the peripheral injection of MSG increases their secretion of thyroxine and TSH. These findings imply that glutamate plays a role in controlling a man's output of thyroid hormones and TSH