Objective To research whether th ere were developmental defects in the anterior pituitary of Tianjin Albino 3 dwa rf mi ce (dw t). Methods In this study immunocytochemical and ster eological methods were employed.ResultsThe volumetric den sity (Vv) and numerical density (Nv) of the TSH immunoreactive cells were reduce d in both male and female dw t mice as compared with those in the normal contro l mice.ConclusionIt is suggested that the number decrease of the TSH cells in dw t mice leads to the deficiency of TSH secretion.