Abstract
We examined the effects of bromocriptine on the ultrastructure and on the levelsof messenger RNA (mRNA) of prolactin and growth hormone (GH) in a cultured GH3 cell line. Prolactin and GH concentrations measured by radioimmunoassay in the incubation medium as well as the cell number of the GH3 cells were significantly decreased by treatment with 10-4M bromocriptine for 24 hours. Electron microscopy of bromocriptine—treated GH3 cells demonstrated accumulation of cytoplasmic vacuoles containing cytoplasmic components including secretory granules (crinophagy) which were positive for acid phosphatase staining. The remarkable morphological changes in GH3 cells, induced by treatment with 10-4M bromocriptine for 24 hours, disappeared 48 hours after substitution with bromocriptine-free medium. An immunoelectron-microscopic study demonstrated gold particles binding with antiprolactin antibodies not only In the cytoplasm but also inside vacuoles of GH3 cells after incubation with bromocriptine for 24 hours. Treatment with 10-4M bromocriptine for 24 hours caused the reduction both of mRNAs of prolactin measured by dot-blot hybridization and the Northern-blotting method and of GH measured by the Northern-blotting method. In conclusion, bromocriptine induces a reversible lysosomal change and could inhibit gene transcription of prolactin and GH in GH3 cells.Endocr Pathol 4:28–33, 1993.
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Kamijo, K., Sato, M., Saito, T. et al. Bromocriptine-induced reversible lysosomal change and reduction of prolactin and growth hormone messenger RNA in cultured GH3 cell lines. Endocr Pathol 4, 28–33 (1993). https://doi.org/10.1007/BF02914486
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DOI: https://doi.org/10.1007/BF02914486