Thyroid-stimulating hormone receptor and thyroid hormone receptors are involved in human endometrial physiology

Objective: To study the expression, distribution, and function of thyroid-stimulating hormone receptor (TSHR) and thyroid hormone receptors (TR) alpha 1, alpha 2, and beta 1 in human endometrium. Design: Experimental clinical study. Setting: University hospital. Patient(s): 31 fertile women. Intervention(s): Endometrial biopsy samples obtained throughout the menstrual cycle. Main Outcome Measure(s): Real-time reverse transcriptase polymerase chain reaction, immunohistochemistry and Western blot to study the expression of TSHR, TR alpha 1, TR alpha 2, and TR beta 1 messenger RNA (mRNA) and proteins in human endometrium. Result(s): We found TSHR, TR alpha 1, TR alpha 2 and TR beta 1 mRNA and proteins expressed in human endometrium. Immunostaining for TSHR in the luminal epithelium and TR alpha 1 and beta 1 in the glandular and luminal epithelium increased statistically significantly on luteinizing hormone (LH) days 6 to 9, coinciding with appearance of pinopodes. Endometrial stromal and Ishikawa cells expressed mRNA for TSHR, TR, and iodothyronine deiodinases 1-3. After 48 hours, TSH significantly increased leukemia inhibitory factor (LIF) and LIF receptor (LIFR) messenger RNA (mRNA) in endometrial stromal cells, but decreased their expression in Ishikawa cells. Glucose transporter 1 mRNA was up-regulated by TSH in Ishikawa cells. We found that TSH statistically significantly increased secretion of free triiodothyronine (T-3) and total thyroxin (T-4) by Ishikawa cells compared with nonstimulated cells. Conclusion(s): Thyroid hormones are directly involved in endometrial physiology. (Fertil Steril(R) 2011;95:230-7. (C) 2011 by American Society for Reproductive Medicine.)