ISSN:
0003-276X
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
The follicular cells of thyroid glands of intact rats respond to TSH challenge by an intense mitotic stimulation and a higher functional activity as measured by the epithelium height. In hypophysectomized rats the same intense response was observed when the thyroid was challenged immediately after hypophysectomy. However, one week later the mitotic response was almost completely absent and the functional response much weaker. This indicates that, although TSH is the main regulating factor of the functional activity and cell proliferation of the thyroid follicle, its effect is conditioned by additional factors. These factors may originate both from the anterior and/or posterior pituitary, since a significantly higher response was obtained by injecting anterior or posterior pituitary powder during the interval between hypophysectomy and TSH challenge. Prolactin, vasopressin and oxytocin also boosted the mitotic response to TSH. Posterior pituitary powder alone (without TSH challenge) was not mitogenic for the thyroid gland either in intact or hypophysectomized rats, while it was mitogenic for the adrenal glomerulosa. The low thyroid mitotic responsiveness does not reflect a general unspecific effect on mitoses of all cells, since the esophageal epithelium was not similarly affected by hypophysectomy or by replacement therapy.
Additional Material:
3 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/ar.1091800210
