[Analysis of circulating thyroid-stimulating activities in pregnant women with Graves' disease: differential measurement of activities induced by TSH receptor antibody and hCG].
Thyrotoxicosis in Graves' disease is often aggravated in early pregnancy and this aggravation is associated with postpartum relapse of thyrotoxicosis. To examine whether thyroid-stimulating TSH receptor antibody (TSAb) or human chorionic gonadotropin (hCG), which also has thyroid-stimulating activity (TSA), is responsible for this early aggravation, the respective TSA due to TSAb or hCG were evaluated with a sensitive cAMP accumulation assay using FRTL-5 cells. TSA, which was detectable in all of 11 women in normal early pregnancy, correlated positively with serum hCG level, but was abolished completely by the pretreatment of serum samples with the solid-phase hCG antibody coupled with Sepharose-4B. Total TSA in the model samples of mixture of Graves' and pregnant sera (Gr + Preg), was reduced by the pretreatment with the solid-phase antibody, just corresponding with the reduction in hCG-induced TSA. Total TSA in early pregnant sera in 15 patients with Graves' disease, decreased significantly but was still positive even by the pretreatment with the hCG antibody. Pregnancy-associated changes in TSA was examined serially in a patient with Graves' disease, and hCG-induced TSA increased predominantly along with the serum thyroid hormone in early aggravation period. These data indicate that (1) the respective TSA due to TSAb or hCG can be differentially measured by using the solid-phase hCG antibody and (2) hCG plays an important role for aggravation of Graves' thyrotoxicosis in early pregnancy.
Kaneda
T
T
Department of Laboratory Medicine, Osaka University Medical School.
Tamaki
H
H
Hidaka
Y
Y
Amino
N
N
Mitsuda
N
N
Tanizawa
O
O
Miyai
K
K
D000818:Animals; D000906:Antibodies / Q000097:blood*; D006063:Chorionic Gonadotropin / Q000097:blood*; D005260:Female; D006111:Graves Disease / Q000097:blood*; D006801:Humans; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood*; D051381:Rats; D011989:Receptors, Thyrotropin / Q000276:immunology*; D013971:Thyrotoxicosis / Q000097:blood*
D000906:Antibodies; D006063:Chorionic Gonadotropin; D011989:Receptors, Thyrotropin