Thyroid hormone stimulates alkaline phosphatase activity in cultured rat osteoblastic cells (ROS 17/2.8) through 3,5,3'-triiodo-L-thyronine nuclear receptors

To investigate the increased alkaline phosphatase activity of bone origin in patients with hyperthyroidism, we studied the thyroid hormone effects on alkaline phosphatase activity in a clonal rat osteoblastic cell line (ROS 17/2.8). T4 and T3 increased alkaline phosphatase activity in ROS 17/2.8 cells in a dose-dependent manner. The minimal effective T4 and T3 concentrations in medium containing 10% thyroid hormone-depleted fetal calf serum were 10(-8) M (free T4, 8 X 10(-11) M) and 10(-9) M (free T3, 4 X 10(-11) M), respectively. ROS 17/2.8 cells possessed high affinity, low capacity nuclear receptors specific for T3 [dissociation constant (Kd) approximately 150 pM; maximal binding capacity, approximately 2000 T3 binding sites per nucleus]. The relative affinity of T3, T4, rT3, MIT, and DIT were in good agreement with their biological activity. These findings suggest that rat osteoblast-like cells contain T3 nuclear receptors and that alkaline phosphatase activity is stimulated by thyroid hormone via a nuclear receptor-mediated process at free thyroid hormone concentrations attainable in patients with Graves' disease.

3,3',5'-Triiodothyronine inhibits iodothyronine-5'-deiodinating activity induced by 3,5,3'-triiodothyronine at equimolar concentrations in cultured fetal mouse liver

To investigate the rT3 effect on iodothyronine-5'-deiodinating activity (I-5'-DA) in cultured fetal mouse liver, liver on the 19th day of gestation, in which little or no I-5'-DA was detected and, therefore, rT3 was very stable, was cultured in medium containing thyroid hormone-depleted fetal calf serum supplemented with cortisol, insulin, and various concentrations of iodothyronines. After 4-15 days of culture, I-5'-DA in the homogenate was assessed by the amount of iodide released from outer ring-labeled rT3 and expressed as picomoles of 127I- per mg protein/min. I-5'-DA was induced by T3 (10(-9)-10(-8) M) and T4 (10(-7) M). In contrast, rT3 could not induce I-5'-DA at 10(-8)-10(-6) M. Furthermore, rT3 significantly decreased I-5'-DA induced by T3 (10(-8) M) at almost equimolar concentrations (1-5 X 10(-8) M). The inhibitory action of rT3 was reversible and was specific for I-5'-DA; no alteration in malic enzyme activity or intracellular glutathione concentration was detected. The inhibitory effect of rT3 on I-5'-DA was dose dependent, and the enzyme activity decreased with a half-life of 16 h in the presence of 10(-6) M rT3. The inhibitory effect was not due to contaminating rT3 in the liver homogenates. Lineweaver-Burk analysis revealed that the decrease in I-5'-DA was due to a decrease in the maximum velocity, whereas no alteration in Km was detected, suggesting that rT3 decreases the amount of 5'-deiodinase induced by T3. The minimal free rT3 concentration capable of inhibiting the induction of iodothyronine-5'-deiodinase was approximately 10(-10) M, which may be attainable in vivo, as in amnionic fluid. In summary, we have demonstrated that rT3 exerts a strong antagonistic effect against T3 in inducing I-5'-DA in cultured fetal mouse liver.

Production of bone-resorbing activity and colony-stimulating activity in vivo and in vitro by a human squamous cell carcinoma associated with hypercalcemia and leukocytosis

A squamous cell carcinoma of 33-yr-old patient who developed marked leukocytosis and hypercalcemia was transplanted into nude mice in which more marked leukocytosis and hypercalcemia also developed. This tumor (LJC-1-JCK) produced a colony-stimulating factor (CSF) and formed a cyst in the tumor from which a CSF-producing cell line (T3M-1) was established. The CSF causes predominantly formation of granulocytic colonies in addition to macrophage colonies. Bone-resorbing activity (BRA) was detected in the cystic fluid and was eluted as two separate peaks with proteins of an apparent molecular weight of 30,000-50,000 and 10,000-20,000. Colony-stimulating activity (CSA) was eluted at an apparent 30,000 mol wt. The conditioned medium of the T3M-1 cells also contained a BRA with an apparent 14,000 mol wt, whereas CSA eluted at an apparent 30,000 mol wt. PTH, epidermal growth factor, transforming growth factor-alpha, prostaglandin Es, and vitamin D could not account for the powerful BRA. In contrast to CSA, BRA was not inactivated by trypsin and more stable at 70 degrees C. When T3M-1 cells were transplanted into nude mice, marked hypercalcemia developed in addition to granulocytosis. Our findings suggest that the tumor produces and secretes a powerful BRA in vivo and in vitro, which is different from CSA in terms of molecular weight, heat stability, and trypsin treatment. We speculate that the synergistic action of CSF that stimulates macrophage colony formation and recruits osteoclast precursors, and BRA, which stimulates mononuclear phagocytes and/or osteoclasts were responsible for a marked increase in osteoclastic bone resorption and humoral hypercalcemia in the patient.

Primary aldosteronism with normal aldosterone levels in blood and urine

A 47 year old women examined for hypertension (200/100 mmHg) was normokalaemic, and had low plasma renin activity (PRA) (0.1 ng/ml X h) and normal aldosterone levels in both plasma (7-13 ng/dl) and urine (4.7-7.4 micrograms/day). Computed tomography (CT) and scintiscan indicated an adenoma on the right adrenal gland, which was then removed. The histology of the adenoma and analysis of the aldosterone content were compatible with the criteria for an aldosterone-producing adenoma. Three months after surgery, her hypertension had improved, serum potassium levels had increased slightly, and PRA had normalized. This was an unusual form of primary aldosteronism which showed normal levels of aldosterone in both blood and urine.

Graves' disease with neutropenia and marked splenomegaly: autoimmune neutropenia due to propylthiouracil

A 38-year-old man with Graves' disease taking propylthiouracil (PTU) for 6 years developed neutropenia and marked splenomegaly. After subtotal thyroidectomy with discontinuance of PTU the patient remained asymptomatic for the last two and half years. The serum obtained during the period of neutropenia demonstrated opsonic activity to neutrophils of the patient as well as of normal volunteers. This opsonic antineutrophil activity was located in the IgG fraction of the serum. Furthermore, PTU at the concentration (0.1-1.0 micrograms/ml) attainable in the patient's serum significantly stimulated [3H] thymidine incorporation in the patient's lymphocytes. These findings indicate that the patient developed autoimmune neutropenia by producing opsonic antineutrophil antibodies in association with the PTU therapy.

Ontogenesis of iodothyronine-5'-deiodinase. Induction of 5'-deiodinating activity by insulin, glucocorticoid, and thyroxine in cultured fetal mouse liver

To elucidate the regulatory mechanism of ontogenetic development of iodothyronine-5'-deiodinase in the fetal and neonatal period, fetal mouse liver of the 19th day of gestation, in which no iodothyronine-5'-deiodinating activity was detectable, was cultured in Dulbecco-Vogt medium supplemented with 10% thyroid hormone-depleted fetal calf serum, insulin, hydrocortisone, and thyroid hormones. Iodothyronine-5'-deiodinating activity of the homogenate was assessed by the amount of iodide released from outer-ring-labeled reverse T3 and expressed as picomoles of 127I- per milligram of protein per minute. The enzyme activity was induced in a dose-dependent manner; optimal concentrations for insulin, hydrocortisone, and thyroxine were 1 microgram/ml, 0.4 microgram/ml, and 10(-6) M, respectively. Without supplementation of either hydrocortisone or thyroxine, no 5'-deiodination was detected. The enzyme activity was observed after 3 d of culture, peaked at days 14-20, and then gradually decreased. Lineweaver-Burk analysis revealed that the increase in activity was primarily due to an increase in Vmax (day 3, 0.2 pmol/mg protein per min; day 20, 2.5 pmol/mg protein per min). Half maximal thyroxine (T4) and triiodothyronine (T3) concentrations were 1 X 10(-7) M (free T4: 4 X 10(-10) M), and 2 X 10(-9) M (free T3: 5.0 X 10(-11) M), respectively, whereas reverse T3 did not elicit any activity at 10(-8)-10(-6) M. These results suggest that ontogenetic development of iodothyronine-5'-deiodinase in the liver of the fetal and neonatal mouse is induced by physiological concentrations of glucocorticoid and thyroid hormones, and that insulin plays a permissive role in enhancing T3 formation from T4 in the liver.

Rectal malacoplakia in a patient with Hodgkin's disease. Report of a case and review of the literature

A 37-year-old man was found to have classic malacoplakia of the rectum after three courses of chemotherapy for stage IV Hodgkin's disease. Sigmoidoscopy with excisional biopsy was performed because of rectal bleeding. The biopsy specimen of the rectal lesion showed focal extensive granulomatous changes with large macrophages containing round, dense Michaelis-Gutmann bodies. Electromicroscopy demonstrated calcifying spheres with laminated concertric structures (Michaelis-Gutmann bodies) and coliform bacillus in the cytoplasm of macrophages (Von Hansemann bodies). Review of the literature revealed that association of malacoplakia with Hodgkin's disease has never been documented, although it has been reported to be associated with conditions such as malignancy, organ transplantation, collagen disease, and leukemia. The possible role of immune disturbance as an underlying cause of malacoplakia is discussed.