Parathyroid Growth: Normal and Abnormal
Rao SD, Bhadada S, Parfitt AM. Parathyroid Growth: Normal and Abnormal. The Parathyroids: Basic and Clinical Concepts: Third Edition 2015; :255-278.
The Parathyroids: Basic and Clinical Concepts: Third Edition
The functional performance of every endocrine gland requires delivery of the right number of hormone molecules into the circulation during each successive interval of time. Total hormone secretion comprises the aggregate contribution of each cell and so depends not only on the average secretion per cell, but also on the number of contributing cells. The regulation of cell number should receive as much attention as the regulation of individual cell behavior, but in practice it is almost entirely ignored. Cell number is never considered explicitly in the description of feedback relationships. There are several reasons for this neglect. The rules of development normally ensure that each organ grows to the right size, so that adult cell number varies only over a two- to three-fold range. By contrast, hormone secretion by many endocrine glands can vary acutely over as much as a 100-fold range, which must reflect changes in the performance of individual cells. Another reason is that the endocrine glands are among the smallest of organs.Every parathyroid disorder considered in this book is a reflection of, or at least is associated with, characteristic changes in the number of functioning parathyroid cells. Understanding the mechanisms whereby parathyroid cells are able to change their number is not only essential to a full understanding of pathogenesis, but is also relevant to both medical and surgical treatment.