Thyrotropin is not a growth factor for human thyroid cells in culture

Abstract

Thyroid cells, obtained from both normal human tissue and benign nodular goiter, were cultured and maintained in vitro in 4-18 passages. Cultures with confluent cells accumulated cyclic AMP (10-150 times the basal amount) upon addition of bovine thyrotropin (100 milliunits/ml), indicating that the cells in culture maintained a thyrotropin-sensitive adenylate cyclase system. Addition of high doses of thyrotropin also induced a characteristic and reversible change in the morphology of the cells.The effect of thyrotropin on cell growth was studied in short- (HtTh 14). The tissue was fragmented with a scalpel, suspended in phosphate-buffered saline containing 1 mg of collagenase per ml, and incubated in a 37°C rocking waterbath for 60 min. Cells were further liberated from the fragments by pipetting. Large fragments were allowed to sediment and the supernatant was decanted and centrifuged (200 X g for 10 min). The pellets were suspended in Eagle's minimum essential medium (14) supplemented with 10% fetal calf serum, 100 units of penicillin, 1.25 ,gg of amphotericin B, and 50 ,ug of streptomycin per ml. The cells were incubated in 50-mm Nunc petri dishes (Nunc, Roskilde, Denmark). About 20 dishes were initiated from 1 g of wet weight tissue. The cultures were incubated at 37°C in a humidified atmosphere containing 5% CO2. Primary confluent monolayers were usually formed within 7-14 days. The cultures were then subcultivated at 1:2 split ratio. Cells were detached after incubation in phosphate-buffered saline with 0.02% EDTA for 5 min followed by a film of phosphate-buffered saline with 0.25% trypsin for about 10 min. Cultures of normal human skin fibroblasts and human glial cells were initiated and maintained as described (15,16 Abbreviation: TSH, thyrotropin.

Long-term culture and functional characterization of follicular cells from adult normal human thyroids.

“…In contrast to what has been reported for FRTL5 cells (1)(2)(3), the presence of added bovine TSH did not stimulate the DNA synthesis of HNTB-2K cells. Acutely added bovine TSH, alone or in the presence of insulin, did not act as a growth factor for human cells under the conditions described here, confirming earlier observations on human cultures (8,19).…”

Factors controlling proliferation and differentiation of canine thyroid cells cultured in reduced serum conditions: effects of thyrotropin, cyclic AMP and growth factors

“…The cells were proved at any time of the culture to be follicular thyroid cells: (1) they all responded to TSH and agents increasing or mimicking cyclic AMP by the appearance of the characteristic cytoplasmic arborization previously described in other thyroid cultures (Rapoport and Jones, 197X;Westermark et al, 1979;Westermark and Westermark, 1982;Westermark and Porter, 1982). This easily observed response has already been used as strong evidence for the follicular and TSH-responsive nature of thyroid cells in culture (Westermark et al, 1979;Westermark and Westermark, 1982); (2) With 1% serum the hormone-supplemented medium used is relatively well defined. As compared to previously used 15% serum medium, it allows the demonstration of the requirement for several factors (insulin, ascorbic acid) and of much greater effects of TSH and agents increasing cyclic AMP levels or mimicking its action .…”

CD4+ T Cell-Mediated Cytotoxicity Toward Thyrocytes: The Importance of Fas/Fas Ligand Interaction Inducing Apoptosis of Thyrocytes and the Inhibitory Effect of Thyroid-Stimulating Hormone

“…In vitro studies, however, failed to demonstrate the same results in cultured human thyrocytes (Dumont, 1971;Valente et al, 1983;Wadeleux and Winard, 1981;Westermark et al, 1979). The addition of cyclic adenosine monophosphate (cAMP) also suppressed Fas-mediated apoptosis of thyrocytes, and both TSH and TSAb containing IgG increased cAMP level in thyrocytes Kawakami et al, 1997b), suggesting that TSH and TSAb act on thyrocytes in a similar manner to functional Fas expression on thyrocytes.…”