Expression of thyroid-stimulating hormone receptor in thyroid tissue of lactating rats

Abstract

Objective To observe the expressions of thyroid-stimulating hormone receptor (TSHR) protein and mRNA in thyroid gland of lactating rats. Methods Eighty adult Wistar rats (60 females and 20 males), weighting 210-250 g were selected. The 60 female Wistar rats were divided into 6 groups according to their body weight by means of random number table: normal non-pregnant group, lactating for 5, 10, 15 and 20 days groups and weaning for 5 days group, 10 rats in each group. All rats were fed with conventional fodder and tap water freely, and the rats of lactating groups except the normal non-pregnant group cohabited with male rats (3∶1). Then all rats were killed on the 5th, 10th, 15th and 20th day after lactation and on the 5th day after weaning to get thyroid tissues. The expressions of TSHR protein and mRNA were determined by immunohistochemical staining and real-time quantitative PCR. Results TSHR protein was expressed in cytoplasm and membrane of rat thyroid follicular cells. The expression of TSHR protein in thyroid gland was significant different statistically between groups (χ2 = 11.227, P 0.05). The expression of TSHR mRNA in thyroid gland was significantly different statistically between groups (F = 2.970, P 0.05). Conclusion TSHR is widely expressed in thyroid gland of lactating rats, but relatively lower in early lactation period. Key words: Thyroid-stimulating hormone receptor; Thyroid gland; Rats