Quantitative and three‐dimensional aspects of the rat parathyroid gland in normo‐, hypo‐, and hypercalcemia
- 1 October 1995
- journal article
- research article
- Published by Wiley in Microscopy Research and Technique
- Vol. 32 (2) , 129-147
- https://doi.org/10.1002/jemt.1070320208
Abstract
The ultrastructure of the rat parathyroid has been under study for more than 35 years, but controversies still exist, especially regarding structure‐function relationships. The present review focuses on recent morphological parathyroid research on rats under normal conditions and in various states of disturbed calcium metabolism. To facilitate discussions on functional aspects, current biochemical data, particularly those dealing with the regulation of parathyroid hormone synthesis and release, are also considered. Our results from quantitative studies and from investigations employing serial sectioning form the basis for the discussions. A central issue is whether the parathyroid secretory cells undergo secretory cycles. Prompted by results obtained from improved fixation procedures and serial sectioning, we question the basis for the theory of secretory cycles. Since the rat parathyroid secretory cell is polar, a single section is not an appropriate sample for estimating functional activity and for comparing the structure and distribution of intracellular components of adjacent cells. The heterogeneity in ultrastructural appearance of intracellular vesicles calls for the use of specific markers in relating the structure of the vesicular compartment to intracellular processing of hormone. The importance of unbiased quantitative techniques is illustrated in discussions on cell number and size for estimating the response of the parathyroid gland to different functional states or disorders demanding changes in secretion of parathyroid hormone, e.g., hyper‐ and hypocalcemia.Keywords
This publication has 110 references indexed in Scilit:
- Heterogeneous response to calcium by individual parathyroid cells.Journal of Clinical Investigation, 1993
- Effects of estradiol on parathyroid cell activityCellular and Molecular Life Sciences, 1989
- Inhibitors of cellular proteolysis cause increased secretion from parathyroid cellsBiochemical and Biophysical Research Communications, 1989
- The Role of the Vitamin D Endocrine System in Health and DiseaseNew England Journal of Medicine, 1989
- Secretion and degradation of parathormone as a function of intracellular maturation of hormone poolsThe Journal of cell biology, 1979
- Parathyroid hormone biosynthesis. Correlation of conversion of biosynthetic precursors with intracellular protein migration as determined by electron microscope autoradiography.The Journal of cell biology, 1979
- Parathyroid Hormone Responses to Catecholamines and to Changes of Extracellular Calcium in CowsJournal of Clinical Investigation, 1978
- Intracellular Aspects of the Process of Protein SynthesisScience, 1975
- Fine structural alterations of parathyroid glands in response to experimental and spontaneous changes of calcium in extracellular fluidsThe American Journal of Medicine, 1971
- The structural response of the parathyroid glands to ureteral ligation or bilateral nephrectomyThe Anatomical Record, 1945