The respective effects of serum thyroxine and triiodothyronine on serum thyrotropin and lipid parameters in endemic juvenile hypothyroidism.
The respective effects of serum total T4 concentration and of serum total T3 concentration on serum TSH concentration and on lipid parameters were compared in 84 7- to 16-year-old children of the Northern Zaire goitre endemia classified in group A (T4 greater than 77 nmol/l and T3 greater than 1.69 nmol/l), B (low T4, normal T3) and C (low T4, low T3). Mean serum TSH level was normal in group A (2.3 mU/l), it raised to 39.4 mU/l in group B (p less than 0.001) and to 166.3 mU/l in group C (p less than 0.001 vs A and B). Low density lipoprotein cholesterol and apoprotein B were increased in group B vs A (p less than 0.05) and in group C vs A (p less than 0.001) and B (p less than 0.001 for apoprotein B; not significant for cholesterol). High density lipoprotein cholesterol and apoprotein A1 were similar in the three groups. Mean serum triglyceride level, not different in groups A and B, was doubled in group C (p less than 0.001). Multiple regression analysis showed that serum TSH, apoprotein B, and triglyceride levels were influenced by both thyroid hormones concentrations with a predominant effect of serum T4 on the first two parameters and of serum T3 on the last one. In conclusion, low serum T4 with normal T3 concentrations resulted in an increase in serum TSH and in an altered lipid metabolism; it clearly represented an hypothyroid state.
Smitz
J
J
Department of Clinical Chemistry, University Hospital, Free University of Brussels (VUB), Belgium.
Vanderpas
J
J
Yunga
Y
Y
Bourdoux
P
P
Gerlo
E
E
Sevens
C
C
Thilly
C H
CH
D000293:Adolescent; D002648:Child; D015023:Democratic Republic of the Congo / Q000453:epidemiology; D003906:Developing Countries; D005260:Female; D006043:Goiter, Endemic / Q000097:blood* / Q000453:epidemiology; D006801:Humans; D008055:Lipids / Q000097:blood*; D008297:Male; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*
D008055:Lipids; D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine