Summary
In an attempt to assign morphologic identities to previously distinguished functional calcium compartments in the anterior pituitary of the rat, we employed the potassium pyroantimonate technique for cation localization. Tissues were incubated for In at 37°C in control medium; with 10mM theophylline; or with depolarizing amounts of potassium. Precipitate was quantified on photomicrographs of tissue prepared for electron microscopy with a Talos Systems Digitizer. The nature of the electron dense precipitate was dependent on the experimental state of the tissue. Treatment with 5 mM EGTA abolished the dense precipitate. Electron microprobe analysis also confirmed that calcium was the predominant cation in the observed precipitate. The most significant changes in precipitate deposition occurred along the plasma membrane, the limiting membrane of secretory granules and within mitochondria. Dense precipitate was present along the plasma membrane only in cells treated with potassium. Control tissue exhibited higher levels of precipitate associated with the limiting membrane of secretory granules than either theophylline-treated or potassium-treated tissue. Mitochondria contained more precipitate in potassium-treated tissue than in controls; the mitochondria of theophylline-treated tissue contained intermediate levels of precipitate. Addition of either theophylline or depolarizing amounts of potassium has been associated with hormone secretion in anterior pituitary tissue of normal rats. Kinetic studies in our laboratory indicate that intracellular calcium shifts occur. The pyroantimonate technique is useful in verifying morphologically the calcium compartments involved in shifts in intracellular calcium.
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References
Borle AB (1974) Cyclic AMP stimulation of calcium efflux from kidney, liver, and heart mitochondria. J Membrane Biol 16:221–236
Borle AB (1976) Cyclic AMP stimulation of calcium efflux from isolated mitochondria: A negative report. J Membrane Biol 29:209–210
Cramer EB, Cardassis C, Pereira G, Milks L, Ford D (1978) Ultrastructural localization of cations in the rat pars distalis under various experimental conditions. Neuroendocrinol 26:72–84
Dular R, LaBella F (1977) Action of releasing factors on isolated secretory granules mediated by calcium. Life Sci. 21:1527–1534
Eto S, Wood JM, Hutchins M, Fleischer N (1974) Pituitary 45Ca++ uptake and release of ACTH, GH, and TSH: Effect of verapamil. Am J Physiol 226:1315–1320
Kraicer J (1975) Mechanisms involved in the release of adenohypophysial hormones. In: Tixier-Vidal, A, and Farquhar MG (eds) The anterior pituitary, pp, 21–43, Academic Press, New York
Matlib A, O'Brien JP (1974) Adenosine 3′∶5′-cyclic monophosphate stimulation of calcium efflux from mitochondria. Biochem. Soc. Trans. 2:997–1002
Moriarty CM (1977) Involvement of intracellular calcium in hormone secretion from rat pituitary cells. Mol Cell Endocrinol 6:349–361
Moriarty CM (1978) Role of calcium in the regulation of adenohypophysial hormone release. Life Sci 23:185–194
Moriarty CM (1980) Kinetic analysis of calcium distribution in rat anterior pituitary slices. Am J Physiol 238:E167-E173
Scarpa A, Malstrom K, Chiesi M, Carafoli E (1976) On the problem of the release of mitochondrial calcium by cyclic AMP. J Membrane Biol 29:205–208
Schechter JE (1976) Cations in the rat pars distalis: ultrastructural localization. Am J Anat 146:189–206
Sternberger LA, Petrali JP (1975) Quantitative immunocytochemistry of pituitary receptors for luteinizing hormone-releasing hormone. Cell Tissue Res 162:141–176
Stoeckel ME, Hindelang-Gertner C, Dellmann HD, Porte A, Stutinsky F (1975) Subcellular localization of calcium in the mouse hypophysis. Cell Tissue Res 157:307–322, 1975
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Leuschen, M.P., Moriarty, C.M., Sampson, H.W. et al. Cytochemical analysis of intracellular calcium distribution in the anterior pituitary of the rat. Cell Tissue Res. 220, 191–200 (1981). https://doi.org/10.1007/BF00209977
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DOI: https://doi.org/10.1007/BF00209977