TY - JOUR AU - Lakatos, Péter AU - Caplice, M D AU - Khanna, V AU - Stern, P H TI - Thyroid hormones increase insulin-like growth factor I content in the medium of rat bone tissue JF - JOURNAL OF BONE AND MINERAL RESEARCH J2 - J BONE MINER RES VL - 8 PY - 1993 IS - 12 SP - 1475 EP - 1481 PG - 7 SN - 0884-0431 DO - 10.1002/jbmr.5650081210 UR - https://m2.mtmt.hu/api/publication/1802374 ID - 1802374 N1 - Összes idézések száma a WoS-ban: 0 Cited By :44 Export Date: 14 March 2020 Correspondence Address: Stern, P.H.; Department of Pharmacology, Northwestern University Medical School, 303 East Chicago Avenue, Chicago, Illinois, 60611, United States Chemicals/CAS: 3,3',5' triiodothyronine, 5817-39-0, 70-39-3; 3,5 dibromo 3' (2,3 dihydro 3 oxo 6 pyridazinylmethyl)thyronine, 105211-23-2; diiodotyrosine, 66-02-4; liothyronine, 6138-47-2, 6893-02-3; protein, 67254-75-5; somatomedin C, 67763-96-6; thyroxine, 7488-70-2; tiratricol, 51-24-1; 3,3',5-triiodothyroacetic acid, 51-24-1; Culture Media; Insulin-Like Growth Factor I, 67763-96-6; SK&F 94901; Thyroid Hormones; Thyronines; Thyroxine, 7488-70-2; Triiodothyronine, 6893-02-3; Triiodothyronine, Reverse, 5817-39-0; Tumor Necrosis Factor Funding Agency and Grant Number: NIDDK NIH HHSUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute of Diabetes & Digestive & Kidney Diseases (NIDDK) [R01 DK-45269] Cited By :44 Export Date: 15 March 2020 Correspondence Address: Stern, P.H.; Department of Pharmacology, Northwestern University Medical School, 303 East Chicago Avenue, Chicago, Illinois, 60611, United States Chemicals/CAS: 3,3',5' triiodothyronine, 5817-39-0, 70-39-3; 3,5 dibromo 3' (2,3 dihydro 3 oxo 6 pyridazinylmethyl)thyronine, 105211-23-2; diiodotyrosine, 66-02-4; liothyronine, 6138-47-2, 6893-02-3; protein, 67254-75-5; somatomedin C, 67763-96-6; thyroxine, 7488-70-2; tiratricol, 51-24-1; 3,3',5-triiodothyroacetic acid, 51-24-1; Culture Media; Insulin-Like Growth Factor I, 67763-96-6; SK&F 94901; Thyroid Hormones; Thyronines; Thyroxine, 7488-70-2; Triiodothyronine, 6893-02-3; Triiodothyronine, Reverse, 5817-39-0; Tumor Necrosis Factor AB - The mechanism of action of thyroid hormones on bone is still not clear. At low concentrations, they stimulate bone formation; at high concentrations, they elicit bone resorption in vitro and in vivo. In the present study we investigated the effect of T3 and T4 as well as their active and inactive analogs (TRIAC, SKF L-94901, rT3, and DIT) on the IGF-I and TNF-α content in the medium of UMR-106 rat osteoblastic cells and fetal rat limb bones. In the dose-response studies, a biphasic increase in medium IGF-I was observed in both cells and limb bones, with peak stimulatory concentrations of 10-8 M for T3 and 10-7 M for T4 in both systems. At higher concentrations, at which thyroid hormones elicit bone resorption, the stimulatory effect diminished and finally was no longer detectable. The active analogs TRIAC and SKF L-94901 also enhanced IGF-I release in UMR-106 cells. The inactive compounds rT3 and DIT failed to increase IGF-I in these cultures. The protein content of the cell culture wells exposed to high concentrations of thyroid hormones was similar to those containing low concentrations, indicating that the decrease in IGF-I content at high doses was not due to toxic effects. This was also confirmed by trypan blue exclusion. Time course studies with UMR-106 cells revealed a significant increase in medium IGF-I after 2 days of incubation. No significant further increase was observed after this up to 5 days of culture. In contrast, the medium of limb bone cultures showed a linear increase in IGF-I content up to 7 days of culture. No TNF-α production was observed in either UMR-106 cells or fetal limb bones. Also, no increase in medium TNF-α levels was seen in response to thyroid hormones. Based on our results, we conclude that IGF-I may be responsible for some of the anabolic effects of thyroid hormones in bone tissue, but TNF-α, at least in the models we used, does not play a role in the mediation of thyroid hormone action. LA - English DB - MTMT ER - TY - JOUR AU - Lakatos, Péter AU - Stern, P H TI - Effects of cyclosporins and transforming growth factor β1 on thyroid hormone action in cultured fetal rat limb bones JF - CALCIFIED TISSUE INTERNATIONAL J2 - CALCIFIED TISSUE INT VL - 50 PY - 1992 IS - 2 SP - 123 EP - 128 PG - 6 SN - 0171-967X DO - 10.1007/BF00298788 UR - https://m2.mtmt.hu/api/publication/1802377 ID - 1802377 N1 - Manufacturers: sandoz, United States; sigma, United States; smith kline beecham, United States AB - To study the mechanism of action of thyroid hormones on bone, we examined the effects of immunosuppressive and nonimmunosuppressive cyclosporins, as well as of transforming growth factor β1 (TGFβ1), 17β-estradiol (E2), and dihydroxytestosterone (DHT) on thyroxine (T4)- and triiodothyronine (T3)-stimulated bone resorption in fetal rat limb bones. The immunosuppressive cyclosporins A (CsA) and G (CsG) inhibited thyroid hormone (T4 + T3)-stimulated resorption and β-glucuronidase release into the culture medium, whereas the weak or nonimmunosuppressive cyclosporins D (CsD) and H (CsH) did not show this effect. Increasing the medium calcium concentration reduced the ability of T4 to stimulate 45Ca release, while not significantly affecting the response to CsA. TGFβ1 elicited a biphasic effect when administered together with T4. During the first 3 days of culture, TGFβ1 elicited a small, nonsignificant decrease in released 45Ca; during a subsequent 3 days of culture, it enhanced T4-stimulated bone resorption significantly. These effects differed from those of TGFβ1 on parathormone-stimulated resorption. E2 and DHT did not influence the action of T4 on bone tissue. These results suggest that the mechanism of action of thyroid hormones on bone may involve immune factors, as well. LA - English DB - MTMT ER - TY - JOUR AU - Lakatos, Péter AU - Stern, P H TI - Evidence for direct non-genomic effects of triiodothyronine on bone rudiments in rats: Stimulation of the inositol phosphate second messenger system JF - ACTA ENDOCRINOLOGICA J2 - ACTA ENDOCRINOL VL - 125 PY - 1991 IS - 5 SP - 603 EP - 608 PG - 6 SN - 0001-5598 DO - 10.1530/acta.0.1250603 UR - https://m2.mtmt.hu/api/publication/1802379 ID - 1802379 AB - Thyroid hormones increase cytosolic free calcium by binding to plasma membrane receptors in several tissues. This calcium increase appears to initiate extranuclear effects in these tissues. Increases in cytosolic calcium are often a consequence of stimulation of inositol phosphate second messenger pathway. Several calcemic hormones act via this signal transduction route. Therefore we investigated the effects of the metabolically active T3 and the inactive analogues 3,5-diiodotyrosine and rT3 on the inositol phosphate pathway in fetal rat limb bone cultures prelabeled with [3H]myoinositol. Labelled inositol and inositol phosphates were separated by HPLC. There was a significant increase in the radioactivity in inositol bis- and trisphosphates after 1 min of exposure to 10-7 mol/l T3. Stimulation was also observed at 10-6 mol/l T3, but not at 10-5 mol/l. Time course studies demonstrated a rapid effect of T3 on inositol phosphates within 30 seconds that lasted through 5 min. After 20 min incubation with T3, no increase was observed in inositol mono- and bisphoshates, and a decrease was seen in inositol trisphosphate. Pretreatment with indomethacin prevented these effects of T3. 3,5-diiodothyrosine and rT3 did not affect inositol phosphate metabolism. These results suggest the existence of plasma membrane-associated receptors for T3 in bone, in addition to the nuclear receptors demonstrated previously. The role of these receptors in the effects of thyroid hormones on bone remains to be established. LA - English DB - MTMT ER -