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ULTRASTRUCTURAL CHANGES IN THE PARATHYROIDS OF MONGOLIAN GERBILS INDUCED EXPERIMENTALLY IN VITRO Effects of Variations in Ca 2+ and Mg 2+ Concentrations
Author(s) -
Boquist Lennart
Publication year - 1977
Publication title -
acta pathologica microbiologica scandinavica section a pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0365-4184
DOI - 10.1111/j.1699-0463.1977.tb00418.x
Subject(s) - ultrastructure , in vitro , biology , microbiology and biotechnology , anatomy , biochemistry
Isolated parathyroid glands from normal adult Mongolian gerbils were incubated for 15 minutes to 3 1/2 hours either at high or low concentrations of Ca 2+ and Mg 2+ after which they were studied ultrastructurally, using the pyroantimonate technique and x‐ray analysis for identification and structural localization of cations. Glands maintained at high cation concentrations were mainly composed of suppressed chief cells with moderate or high cytoplasmic density, sparsely developed endoplasmic reticulum, often large Golgi complex, occasional cytoplasmic accumulations of secretory granules, lipoid bodies, glycogen‐like particles, and numerous often large mitochondria. Ca 2+ ‐containing precipitates were found mainly in mitochondria. Autophagic vacuoles contained Ca 2+ ‐loaded degenerating mitochondria. Glands exposed to low concentrations of Ca 2+ and Mg 2+ were mainly composed of stimulated and active chief cells; characteristic features were a moderate or low cytoplasmic density, prominent endoplasmic reticulum, small Golgi complex, medium‐sized or small mitochondria, and smooth electron lucent vacuoles with or without an association to mitochondria. Ca 2+ ‐containing precipitates were found mainly in smooth vacuoles and cytosol, but also in mitochondria and rough vacuoles. Myelin‐like figures and crystalloid bodies occurred in some mitochondria, and normal or degenerating mitochondria without Ca 2+ ‐loading were seen in autophagic vacuoles. In addition, some stimulated chief cells exhibited double membrane‐limited sequestered areas of cytoplasm with a rich content of free ribosomes and glycogen‐like particles. The chief cell mitochondria seem to possess capacity for rapid accumulation of Ca 2+ , associated with an increase in volume at functional suppression. At stimulation of parathyroid function the endoplasmic reticulum is prominent in the active cells, and there seems to be a decrease in the volume and Ca 2+ ‐content of the mitochondria occasionally associated with degenerative changes, and a decrease also in the number of free ribosomes and glycogen‐like particles in the stimulated cells.