Urine TRH immunoreactivity in hypothyroid and hyperthyroid patients.

Area of Science:

• Endocrinology
• Biochemistry
• Urology

Background:

• Thyrotropin-releasing hormone (TRH) is a key regulator of thyroid function.
• Measuring TRH in urine may offer insights into thyroid status.
• Previous studies on urinary TRH in thyroid disorders have yielded varied results.

Purpose of the Study:

• To investigate urine TRH-immunoreactivity levels in healthy subjects, primary hypothyroidism, and Graves' hyperthyroidism.
• To assess the relationship between urine TRH levels and thyroid hormone status before and after treatment.
• To determine if urine TRH levels correlate with serum TSH or thyroid hormone levels.

Main Methods:

• Urine samples were collected from 8 healthy subjects, 16 hypothyroid patients, and 8 hyperthyroid patients.
• Samples underwent cation-exchange chromatography and reverse-phase HPLC.
• TRH-immunoreactivity was quantified using radioimmunoassay.

Main Results:

• Healthy subjects had urine TRH levels of 5.5 +/- 1.4 ng/1.
• Hypothyroid patients showed wide variations (50.6 +/- 40 ng/1 pre-treatment, 71.7 +/- 45.3 ng/1 post-treatment), with two exhibiting exceptionally high levels.
• Hyperthyroid patients had urine TRH levels (10.3 +/- 3.9 ng/1 pre-treatment, 8.9 +/- 3.3 ng/1 post-treatment) similar to healthy controls.

Conclusions:

• Urine TRH levels generally do not correlate with serum TSH or thyroid hormone levels in hypothyroidism and hyperthyroidism.
• Two hypothyroid patients with initially very high urine TRH levels showed normalization after 5 and 18 months.
• Urinary TRH measurement may not be a reliable indicator of thyroid status in most patients with thyroid dysfunction.