Hyperparathyroidism induced by hypothyroidism.

The coexistence of hyperparathyroidism and thyroid tumors and/or chronic thyroiditis has raised the possibility of an etiologic relationship. The present study was designed to test the hypothesis that the chronic elevation of thyroid-stimulating hormone (TSH) is related to the development of hyperparathyroidism. Three groups of 24 rats each were treated for 12 weeks as follows: group 1 received propylthiouracil (PTU) in their deionized water; group 2 received PTU and thyroid hormone to suppress TSH and to serve as a control group for possible direct effects of PTU; and group 3 was not treated at all and served as another control group.

High phosphate diet-induced primary hyperparathyroidism: an animal model.

Primary hyperparathyroidism (PHPT) is increasing in incidence and detection, primarily because of the aging of our population and the widespread use of automated serum calcium determination. As a result, a substantial number of "early" cases or "biochemical" PHPT are being detected. The indications for parathyroidectomy in such early cases of PHPT are currently under debate, primarily because of economic issues.

[Hyperparathyroidism and Hashimoto's thyroiditis: coincidence or consequence?].

Primary hyperparathyroidism is commonly associated with Hashimoto's thyroiditis. The raised TSH levels might induce hyperparathyroidism, as suggested by some experimental data. It might also explain the development of hyperparathyroidism after neck irradiation and lithium therapy.

Altered TSH levels associated with increased serum 1,25-dihydroxyvitamin D3: a possible link between thyroid and parathyroid disease.

The physiologic relationship between the thyroid and parathyroid glands remains poorly understood. A high incidence of coexistent thyroid disease and primary hyperparathyroidism has been well documented. Elevation of serum 1,25-dihydroxyvitamin D3 (vitamin D) has been detected in some patients with primary hyperparathyroidism.

Age related correlation between serum TSH and thyroid C cell hyperplasia in Long-Evans rats.

The purpose of the present investigation was to determine whether there is a correlation between the serum levels of thyroid stimulating hormone (TSH), parafollicular cell (C) population in the thyroid and calcitonin (CT) secretion in aging Long-Evans (L-E) rats. Serum TSH and CT values were determined in 50 male rats at ages 2, 6, 12, 18 and 24 months and 50 female rats at 18, 21 and 24 months. The animals were sacrificed at the end of the experiment to evaluate thyroid C cell pathology.