compared to controls , vitamin a-deficient chicks were characterized by thyroid follicle hypertrophy by 4 weeks , heavier thyroids as a percent of body weight at 5 weeks , less serum thyroxine ( t4 ) at 7 weeks and lower serum triiodothyronine ( t3 ) and t4 at 8 weeks .
C0229577
thyroid follicle
C0040132
thyroids