Abstract
A histological study was made of trout and eel pituitaries, cultured on a medium with or without thyroxin. In the trout pituitary cultured without thyroxin, certain cyanophils in the pars distalis show cytoplasmic degranulation and a gradual cellular and nuclear hypertrophy. The addition of thyroxin (20-0.08 μg/ml) to the medium delays this degranulation and causes the cyanophils to regress. Similar changes are shown by the cyanophils in the rostral pars distalis of the eel pituitary in response to thyroxin. It is suggested that these cells are thyrotrophs and that they possess autonomous secretory activity; thyroxin acts directly on the pituitary, inhibiting both TSH release and TSH synthesis. Other cells show no obvious response to thyroxin but the degranulation of both the thyrotrophs and the orangeophils of the proximal pars distalis is retarded by low temperatures.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call