Increased cellular growth of FRTL-5 thyroid cells mediated by discontinuous stimulation with bTSH.

Abstract

Previous reports showed pulsatile secretion of TSH in man. Therefore, we investigated the effect of discontinuous versus continuous TSH stimulation on the cellular level of FRTL-5 thyroid cells, namely the expression of a nuclear proliferation antigen (NPAg). The expression of this antigen correlates linearly with the 3H-thymidine incorporation and is a marker for cellular growth. The FRTL-5 cells were stimulated for 4 hours with bTSH (0.01-1.0 U/l). Compared to continuously stimulated cell cultures the discontinuous stimulation of FRTL-5 cells with bTSH showed a significant higher rate of NPAg expression, i.e. cellular growth.