Three-dimensional imaging of hormone-secreting cells and their microvesselenvironment in estrogen-induced prolactinoma of the rat pituitary gland byconfocal laser scanning microscopy

This study focused on the three-dimensional imaging of hormone-secreting ce lls and their microvascular environment in estrogen-induced prolactinoma of the rat pituitary gland. Adult female Wistar-Imamichi rats were injected w ith estradiol dipropionate and killed 7 weeks later. Some rats given estrog en for 7 weeks also were injected with bromocriptine before killing. To obt ain a detailed three-dimensional image of microvessels, dialyzed fluorescei n isothiocyanate (FITC)-conjugated gelatin was injected into the left ventr icle of the rat heart. After the perfusion, the pituitary glands were resec ted and subjected to immunohistochemistry (IHC). To evaluate the effects of estro-en and bromocriptine, IHC was performed with antibodies against prol actin (PRL), adrenocorticotropic hormone (ACTH), and growth hormone (GH). W ith the combination, microvessels and cells containing PRL, ACTH, and GH co uld be clearly identified by confocal laser scanning microscopy (CLSM). The PRL cells increased in number and became hypertrophic after prolonged expo sure to estrogen. With bromocriptine administration after estrogen treatmen t, however, PRL cells decreased in number and became atrophic. The current study revealed that estrogen and bromocriptine had significant effects on P RL secretion and the microvascular environment. Therefore, this technique ( FITC injection and IHC) with CLSM is suitable for the three-dimensional ima ging of hormone-secreting mechanisms under various conditions.