INFLUENCE OF EGF ON THE RELATIVE VOLUMES OF COLLOID, EPITHELIUM AND STROMA AND ON THYROCYTE NUCLEI SIZE IN RAT THYROID LOBES IN VITRO.
The epidermal growth factor (EGF) is believed to be a potent growth factor for the thyroid gland. In the present study, we have examined the relative volumes of the main histological compartments (colloid, epithelium and stroma) and the size of thyrocyte nuclei (the mean volume, the mean intersection area and the mean perimeter) in the rat thyroid lobes incubated in vitro for 18 hrs with EGF, applied in 5 different concentrations: 0.1, 1.0, 10, 100 and 1000 ng/ml. Morphometric evaluation was performed, using a computer image analysis system, developed by us. We found that EGF - in concentration of 100 ng/ml - increased the relative volume of stroma when compared to controls, as well as to all the other groups incubated in exposure to that growth factor (used in different concentrations); at the same time, EGF decreased the relative volume of epithelium in the thyroid gland (statistical significance has been recorded only vs. EGF concentrations of 10 ng/ml and 1000 ng/ml). On the other hand, we observed that EGF - in concentration of 100 ng/ml - significantly increased the mean nuclear volume and the mean intersection area of thyrocyte nuclei when compared to the controls, as well as to EGF in concentrations of 1 ng/ml and 1000 ng/ml. With regards to the mean perimeter, a significant increase of its length was noted in the EGF(100 ng/ml)-exposed group vs. the group incubated with an addition of EGF (1 ng/ml).
Brzezinski
J
Department of Endocrine Surgery, Institute of Endocrinology, Medical University of Lodz, Poland.
Slowinska-Klencka
D
Lewinski
A
Klencki
M
Gesing
A
Stasiolek
M
Sowinska-Neuman
L