The effect of bromocriptine on the morphological features of a clonal strain derived from human pituitary adenoma [18-54, SF cells (SF cells)] was studied. Bromocriptine was added to serum-free medium at concentrations of 1 and 10 μg/m
l. After 24 hours, 3 days, and 7 days of cultivation, each cell was observed under both phase-contrast microscopy and transmission electron microscopy. Immunocytochemical staining for prolactin (PRL) was also made.
The phase-contrast microscopic study disclosed that untreated SF cells had angular or polygonal shapes. Ultrastructurally they were characterized by the presence of numerous free ribosomes, many mitochondria, well developed rough endoplasmic reticuli (RER) and Golgi complex, and especially by the lack of secretory granules in the cell. Immunoreactive products for PRL were observed throughout the cytoplasm. These cells showed little change after the administration of 1 μg/m
l of bromocriptine all through the study. On the other hand, the cisternal spaces of the RER were dilated to varying degrees, and many vacuoles originating from the RER cisternae were observed in the cytoplasm 3 days after the administration of 10 μg/m
l of bromocriptine. Mitochondria were decreased in number and size, and the electron density of their matrix was increased at this stage. Seven days after the administration of 10 μg/m
l of bromocriptine, electron microscopy disclosed the following; pyknosis of nuclei, atrophy or swelling of mitochondria, increased cytoplasmic electron density, and severe degeneration in a large number of cells. No degenerative changes were observed in fetal mouse glial cells when 10 μg/m
l of bromocriptine was administered (control group).
The results suggest that bromocriptine has a cytocidal effect on SF cells and that this effect is a dose- and time-related phenomenon.
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