In vitro toxicological studies with primary cultures of porcine thyrocytes have provided
evidence for good correlation with the in vivo potency of various xenobiotics (Brown,
1987; Reader, 1987; Atterwill and Fowler, 1990). This is a useful technique for
examining compounds that are suspected of interference with organification, and these in
vitro effects can be measured either by iodide incorporation or the perchlorate discharge test (Atterwill et al., 1987).
The direct effect of xenobiotics on either rat pituitary thyrotrophs or thyrocytes can
also be evaluated by measuring the amount of TSH or thyroxine in the in vitro culture
after an appropriate period of incubation.