Delovanje steroidnih hormona na tireotropne ćelije hipofize

Abstract

The pituitary gland is a heterogeneous tissue comprised of several hormone-secreting cells most of which are targeted by sex steroids. Our long-term studies were concentrated on the response of rat pituitary TSH cells to gonadal steroids applied to animals of different age. With this goal, we examined immunoreactive and morphometric, as well as subcellular organization of pituitary TSH cells in rats of both sexes after neonatal and perinatal estradiol-dipropionate (EDP) treatment. The results undoubtedly indicated persistent EDP-related inhibitory changes of tyrotrophs up to the adulthood. At the subcellular level, a delayed differentiation of TSH cells was noticed. Besides, a special attention has been paid to the changes in the structure of immunoreactive TSH cells of middle-aged (14-month-old) rat females, chronically treated with EDP, calcium (Ca) or a combination of EDP and Ca. Based on our results it can be concluded that both EDP and Ca act inhibiting the thyrotrophs under the applied experimental conditions.

Hipofiza je heterogeno tkivo sastavljeno od nekoliko vrsta ćelija koje luče hormone, a na većinu od njih deluju polni hormoni. Naša višegodišnja istraživanja su bila usmerena na proučavanje odgovora hipofiznih TSH ćelija pacova različite starosti na polne steroide. U tom cilju morfometrijski je ispitivana imunoreaktivnost i subćelijska organizacija TSH ćelija hipofize pacova oba pola posle tretiranja estradiol dipropionatom tokom neonatalnog ili perinatalnog perioda života. Dobijeni rezultati nesumnjivo ukazuju na trajne inhibitorne promene tirotropnih ćelija izazvane estradiolom. Te promene se zapažaju sve do zrelosti. Na subćelijskom nivou je uočena odložena diferencijacija TSH ćelija. Osim toga, posebna pažnja je posvećena strukturnim promenama imunoreaktivnih TSH ćelija menopauzalnih ženki pacova (14 meseci), hronično tretiranih estradiolom, ili kalcijumom, ili kombinacijom estradiola i kalcijuma. Na osnovu naših rezultata se može zaključiti da pri primenjenim eskperimentalnim uslovima i estradiol i kalcijum inhibiraju tirotropne ćelije hipofize.