Relationships between plasma thyrotropin receptor antibodies and lipid or lipoprotein parameters in Graves' disease.
Functional thyrotropin receptors (TSH-R) have recently been detected in fat cells but not in liver cells from rat, and it seems that in infant adipocytes stimulatory TSH-R antibodies (TSH-R-ab) act through this receptor pathway, resulting in increased triglyceride catabolism. We investigated the relationships between plasma TSH-R-ab and free thyroxine (FT4) levels and plasma lipid or lipoprotein values in 49 untreated adult women with Graves' disease, all positive for these antibodies. A simple positive correlation (p < 0.01) was found between TSH-R-ab levels and FT4 values (r = 0.40). Simple positive correlations (p < 0.001) were found between triglyceride levels and FT4 (r = 0.51) or TSH-R-ab (r = 0.52) values. Multiple regression analysis confirmed that both FT4 and TSH-R-ab are strong (p < 0.005) predictors of triglyceride (FT4: partial r = 0.40; TSH: partial r = 0.39). Simple negative correlations (p < 0.05, at least) were found between FT4 levels and total cholesterol (TC) (r = -0.45), low-density lipoprotein (LDL)-C (r = -0.46), apoprotein (apo)-B (r = -0.31) or high-density lipoprotein (HDL)-C (r = -0.55) values. Among these lipid parameters, only HDL-C levels (r = -0.31, p < 0.05) correlated to TSH-R-ab values. However, multiple regression analysis revealed that while FT4 is a strong predictor (p < 0.005) of TC (partial r = -0.42), LDL-C (partial r = -0.43) or HDL-C (partial r = 0.47), TSH-R-ab are not. Thus, the apparent positive relationship between TSH-R-ab and HDL-C results from the positive correlation between TSH-R-ab and FT4. In conclusion, this study suggests that stimulating TSH-R-ab are involved in triglyceride metabolism. In contrast to thyroid hormones, these antibodies seem not to be related to cholesterol metabolism.
Rieu
M
M
Department of Endocrinology, Saint Michel Hospital, Paris, France.
Revue
E
E
Bonete
R
R
Nunez
S
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000906:Antibodies / Q000032:analysis*; D005260:Female; D006111:Graves Disease / Q000097:blood* / Q000276:immunology*; D006801:Humans; D008055:Lipids / Q000097:blood*; D008074:Lipoproteins / Q000097:blood*; D008875:Middle Aged; D011446:Prospective Studies; D011989:Receptors, Thyrotropin / Q000276:immunology*; D013974:Thyroxine / Q000097:blood
D000906:Antibodies; D008055:Lipids; D008074:Lipoproteins; D011989:Receptors, Thyrotropin; D013974:Thyroxine