[The expression of G proteins alpha-subunit mRNA in different thyroid diseases].

Objective: To investigate the expression of G proteins alpha subunit mRNA in different thyroid diseases.

Methods: Twenty-three thyroid specimens were obtained during surgery, 5 from patients with Graves' disease (GD), 7 from patients with multinodular goiter (MNG), 6 from patients with eufunctioning thyroid adenoma (EFTA) and 5 from patients with thyroid papillary cancer (TPC). The expression of stimulating and inhibiting G proteins alpha subunit mRNA were determined by reverse transcription-polymerase chain reaction (RT-PCR).

Results: (1) The expression of G(s)alpha mRNA in TPCs (1.67 +/- 0.25) was significantly higher than that in normal thyroids (1.10 +/- 0.14) and MNGs (0.96 +/- 0.31), P < 0.05 and P < 0.01. The expression in GDs (1.47 +/- 0.11) and EFTAs (1.36 +/- 0.28) was significantly higher than that in MNGs (P < 0.05), but comparable to that in normal thyroids. (2) The expression of G(i)alpha-2 mRNA in GDs (0.68 +/- 0.26) was lower than that in MNGs (1.15 +/- 0.35), P < 0.05, but there was no difference in the expression of G(i)alpha-1 and G(i)alpha-3 mRNA among different thyroid diseases.

Conclusion: The results indicated that G(s)alpha could play an important role in the pathogenesis of thyroid papillary cancer and G proteins had different expression in different thyroid diseases.