The Effects of Thyroid-Stimulating Hormone and Thyroid Microsomal Antibody on Thyroid Peroxidase Activity in Human Follicular Cells: A Mini Organ Culture Study.

Abstract

Abstract. Thyroid peroxidase (TPO) is an essential enzyme involved in thyroid hormone synthesis and is closely related to the microsomal antigen which is the target of thyroid microsomal antibody. There have been several reports on direct inhibition of peroxidase activity by thyroid microsomal antibody. We prepared a mini organ culture of thyroid glands obtained at operation, and investigated the localization of thyroid peroxidase activity in follicular cells proliferated around the thyroid tissue blocks by electron microscopy. The development of microvilli containing TPO activity on the cell surface facing the culture medium was observed when normal thyroid tissue or Graves' thyroid tissue was incubated with TSH but in the TSH-free group the development of microvilli was poor and TPO activity was very much decreased. After the addition of serum positive for thyroid microsomal antibody, the TPO activity of the microvilli was retained in 4/6 tissue samples, but it disappeared in 2 cases. Our findings suggested that thyroid peroxidase activity is regulated by thyroid stimulating substances such as TSH and by TPO in tissue.

Genotoxicity of Nitroso Compounds and Sodium Dichromate in a Model Combining Organ Cultures of Human Nasal Epithelia and the Comet Assay

“…Although observations in vitro should not be taken as hard evidence for the presence or absence of certain properties in vivo, it is generally accepted that tissue cultures may be valuable in the exploration of functional tissue properties [15]. Therefore, tissue cultures have been used widely to investigate, e.g., arteriosclerosis in cultures of the intima of the aorta [16], hormone production in cultures of the thyroid tissue [17,18], genotoxicity in endometrium cultures [19] and sensitivity against tirapazamine in tumor spheroids [20]. Although the techniques and objectives of these publications are diverse, they share a common aim: ensuring the integrity of cells in their organ-specific structure.…”