Immunohistomorphometric Features of ACTH Cells in Juvenile Rats after Treatment with Estradiol or Human Chorionic Gonadotropin

Abstract

Summary: Estradiol and human chorionic gonadotropin (hCG) are very important in controlling the secretory activity of hormone producing cells in the female rat pituitary glands. The aim of the present study was to examine the morphometric parameters of immunohistochemically la be led ACTH cells in juvenile (16th day) female rat pituitaries after treatment with five doses of estradiol dipropionate (EDP) and two doses of hCG during the neonatal period of life. The controls were treated on the same schedule with an equivalent volume of vehicle. All animals were sacrificed 24 h after the last treatment. ACTH-producing cells were stu died using the peroxidase-antiperoxidase immunohistochemical procedure. The absolute and relative pituitary weights were increased (p<0.05) only in the EDP treated group by 120.0% and by 121.1% respectively, in comparison with the controls. In this group, the volume of ACTH cells, volume of their nuclei and vo lume density were significantly decreased (p<0.05) by 6.4%, 33.3% and 46.2% respectively, compared to the corresponding controls. After treatment with hCG, there were no significant (p>0.05) changes neither in the volume of ACTH cells nor in the volume of their nuclei, in comparison with the controls. On the basis of the results obtained in our study, it can be concluded that EDP, injected into female rats during the neonatal period of life, has an inhibitory effect on the immunohistomorphometric parameters of ACTH cells, but such an effect is not clearly expressed after treatment with hCG. Keywords: ACTH cells, EDP, hCG, female ratsKratak sadr`aj: Estradiol i humani horionski gonadotropin (hCG) veoma su va`ni u kontroli sekretorne aktivnosti }elija hipofize koje proizvode hormone. Cilj ove studije je bio ispitati morfometrijske parametre imunohistohemijski obele`enih ACTH }elija hipofize `enki pacova, u juvenilnom periodu (16. dan), nakon tretmana sa pet doza estradiol-dipropionata (EDP) ili dve doze humanog horionskog gonadotropina (hCG). Kontrole su bile tretirane na istovetan na~in sa odgovaraju}om koli~inom rastvara~a. Svè ivotinje su bile `rtvovane 24 h nakon poslednjeg tretmana. ACTH }elije su bile imunohistohemijski obele`ene metodom peroksidaza-antiperoksidaza (PAP). Dobijeni rezultati ukazuju na zna~ajno pove}anje (p<0,05) apsolutne i relativne mase hipofize za 120% i 121,1% kod `enki tretiranih sa EDP u odnosu na kontrolu. U ovoj grupi `enki pacova volumen ACTH }elija i njihovih jedara, kao i njihova volumenska gustina su bili zna~ajno smanjeni (p<0,05) za 6,4%, 33,3% i 46,2% u pore|enju sa kontrolom. Nakon tretmana hCG-om, volumen ACTH }elija, kao i volumen njihovih jedara, nisu bili zna~ajno (p>0,05) promenjeni u odnosu na kontrolu. Na osnovu dobijenih rezultata moemo zaklju~iti da EDP, injeciran `enkama pacova tokom neonatalnog perioda `ivota, ima inhibitorni efekat na imuno histomorfometrijske parametre ACTH }e lija, {to nije tako jasno izra`eno nakon tretmana hCG-om.

The Effect of Moderate Heat on Rat Pituitary ACTH Cells: Histomorphometric, Immunofluorescent and Hormonal Study

“…The immunohistochemical localization of pituitary ACTH cells was performed using a peroxidase-antiperoxidase (PAP) method [14] as described in detail previously [12,17,20]. In general, after the section's rehydration, 0.3% H 2 O 2 was used for blocking the endogenous peroxidase activity, while non-specifi c staining was reduced by normal porcine serum (DAKO A/S; Glostrup, Denmark).…”

“…Morphometric analyses were conducted as previously described in detail [17][18][19][20][21]. Briefl y, seven immunohistochemically labelled pituitary sections were analysed (two from the superior and inferior part and three sections from the middle part of the gland).…”

Immunohistomorphometric Characteristics Of Pituitary GH Cells In Infant And Peripubertal Female Rats After Treatment With Estradiol Or Human Chorionic Gonadotropin

“…As a continuation of our previous studies in the field of EDP and hCG effects on various pituitary hormone-producing cell histological features in the sensitive periods of female rat life cycle (9,10,11,12), this study is focused on the same, less studied features of developmentally relevant GH cells and relies on up-to-date immunohistomorphometric approach, as a gold standard in modern quantitative histology.…”

“…hCG interacts with the luteinizing hormone/choriogonadotropin (LHCG) receptor (21), while at the level of young female rat pituitary significantly increases the number of FSH and LH, and volume of TSH cells (9,10). ACTH cells upon hCG treatment of juvenile female rats express decreased volume density, while the treatment of peripubertal female rats with the same hormone causes the increase of ACTH cell morphometric parameters (11,12).…”

“…Namely, besides the daily-based pulsatile GH secretion in young individuals of both genders (3), maturing females express the luteinizing hormone (LH) increase coinciding decline in circulating GH/IGF1 levels (4, 5), while high circulating estradiol is followed with GH elevation (6,7,8). Generally, it is well founded that estradiol has stimulatory effect on the pituitary weight of female rats when applied in critical neonatal period of life (9,10,11,12) as well as that increases the number of chromophobes, prolactin (PRL), luteinizing hormone-(LH) and follicle stimulating hormone-(FSH) producing cells (9,13,14,15,16). On the other hand, immunohistomorphometric features of pituitary adrenocorticotropic (ACTH) cells of infant and peripubertal female rats appear decreased upon application of estradiol (11,12).…”