ABSTRACT
The specific anti-rat LH in the peroxidase anti-peroxidase (PAP) immunohistochemical method was used to demonstrate the pituitary gonadotropic cells in the pregnant rats, and then the morphometric analysis method was used to study the change of the number, size and nucleo-cytoplasmic ratio parameters of the gonadotropic cells in pregnant rats after being injected by a high dose of LHRH-A.It was observed that on 24h after injection the number of gonadotropic cells decreased, their size became smaller and their nucleo-cytoplasmic ratio larger: the cell number per mm~3 pituitary tissue was from (4.25?0.21)?10~4 to (2.49?0.14)?10~4; the cell size from 1295?35?m~3 to 895?31?m~3; the nucleo-cytoplasmic ratio from 0.144?0.005 to 0.229?0.010. On 48h after injection these changes were in the process of recovery. On 168h after injection all parameters were recovered.Our observations suggest that after being injected by a high dose of LHRH-A the change of gonadotropic cells in pregnant rats results from the exogenous high dose of LHRH-A which has stimulated gonadotropic cells to release a great amount of LH. It is believed, however, that the changes of gonadotropic cells caused by a high dose of LHRH-A can still return to normal.