Immunohistomorphometric characteristics of pituitary GH cells in infant and peripubertal female rats after treatment with estradiol of human chorionic gonadotropin

Abstract

Th e eff ects of estradiol-dipropionate (EDP) or human chorionic gonadotropin (hCG) on immunohistomorphometric characteristics of pituitary GH cells in infant and peripubertal female rats were investigated. Th e fi rst group of females received fi ve injections of EDP (0.25 mg/kg b.w.) during the neonatal period of life, and was further divided into two subgroups which were sacrifi ced at the infantile period (17th day) or at the peripubertal period (38th day). Th e second group received two doses of hCG (50 IU/kg b.w.) on the 15th and 16th day of life in the fi rst subgroup, and on the 36th and 37th days of life in the second subgroup, while they were sacrifi ced 24 h after the last treatment, respectively. Th e control females were injected with an equivalent volume of the vehicle and sacrifi ced according to the appropriate schedules as the hormone treated rats. EDP treatment decreased GH cell volume density in infant and peripubertal females, by 38% and 76% (p<0.05) respectively, in comparison with the controls. Th e number of GH cells per mm2 in infantile and peripubertal period was decreased in EDP treated animals by 26% and 53% (p<0.05) respectively, compared to the controls. Also, upon EDP treatment in both periods, GH cells were diminished in size and less intensely immunolabelled than in the control groups. Th e morphometric parameters in animals treated with hCG were insignifi cantly changed in both analyzed periods, in comparison with the controls. Unlike hCG, EDP manifested clear inhibitory eff ects on the immunohistomorphometric characteristics of GH cells in examined female rats.

U studiji su ispitivani efekti estradiol dipropionata (EDP) i humanog horionskog gonadotropina na imunohistomorfometrijske karakteristike hipofi znih GH ćelija veoma mladih i peripubertalnih ženki pacova. Prva grupa ženki je tokom neonatalnog perioda života primila pet injekcija EDP-a (0.25 mg/kg b.w.), a naknadno je podeljena na dve podgrupe koje su žrtvovane kao veoma mlade (17. dan) ili u peripubertalnom periodu (38. dan). Druga grupa je primila dve doze hCG-a (50 IU/kg b.w.) 15. i 16. dana života (prva podgrupa), odnosno 36. i 37. dana života (druga podgrupa), a žrtvovane su 24h nakon poslednjeg tratmana, ponaosob. Kontrolne ženke pacova su primile ekvivalentan volumen rastvarača i žrtvovane su po obrascu koji je važio za hormonima tretirane grupe. Tretman EDP-om je prouzrokovao smanjenje volumenske gustine GH ćelija kod veoma mladih i peripubertalnih ženki pacova za 38% odnosno 76% (p<0.05) u poređenju sa kontrolama. Broj GH ćelija po mm2kod veoma mladih i peripubertanih životinja je smanjen nakon EDP tretmana za 26% odnosno 53% (p<0.05) poredeći sa kontrolnim vrednostima. Takođe, tretman EDP-om u oba perioda je izazvao smanjenje dimenzija i intenziteta imunobojenja GH ćelija u odnosu na kontrole. Morfometrijski parametri kod životinja tretiranih hCG-om u oba perioda nisu značajno promenjeni u poređenju sa kontrolnim vrednostima. Za razliku od hCG-a, EDP je ispoljio jasne inhibitorne efekte na imunohistomoprfometrijske karakteristike GH ćelija kod ispitivanih ženki pacova.