Cloning the Fisher Rat Thyroid Cell Line (FRTL-5): Variability in Clonal Growth and 3′5′-Cyclic Adenosine Monophosphate Response to Thyrotropin*

Abstract

To investigate the stability of FRTL-5 cells we cloned stock cells by limiting dilution in a 6-hormone medium with bovine TSH (bTSH) (10 mU/ml) (6H medium). One third of the wells with irradiated fibroblast feeder cells developed FRTL-5 colonies. One hundred and twenty clones were obtained, of which 29 (8%) developed sufficiently for functional analysis. Clones were tested for growth responses to bTSH stimulation as evidenced by 72-h [3H]thymidine uptake and TSH receptor activation by cAMP generation. Clonal growth responses to bTSH were of three types: dose-related growth increase, absence of growth stimulation, and stimulation by bTSH in concentrations up to 100 microU/ml and inhibition of growth above 100 microU/ml. All clones tested showed evidence of extracellular cAMP accumulation in response to bTSH. However, sensitivity to bTSH varied from 1 to 100 microU/ml and maximum cAMP secretion with 1 mU/ml bTSH varied from 2 to 13 pmol/ml. Whereas certain clones showed high sensitivity to bTSH with respect to both growth and cAMP responses (e.g. 1B-6), there were clones which showed disparity in this relationship, as evidenced by poor growth dependency but high cAMP responses or by growth stimulation yet insensitivity with respect to cAMP secretion. These data demonstrate that the FRTL-5 line contains cells with variable responsiveness to bTSH. Whereas the FRTL-5 line is heterogeneous and subject to developmental variation, cloning by limiting dilution allows the derivation of highly bTSH-sensitive cells, such as 1B-6, from the stock cultures.

Transplantable rat thyroid cancer cell line FRTC transformed with muramyl dipeptide

“…This discrepancy may be a result of the difference of the cells. Similar to the previous report (Davies et al, 1987), our FRTL-5 cells also had the chromosomal heterogeneity. Huber et al (1990) have reported that there is extreme individual heterogeneity in human thyroid cells as well as FRTL-5 cells.…”

Differential expression of the thyrostimulin subunits, glycoprotein 2 and 5 in the rat pituitary

“…Indeed, a cross-talk between the immune and neuroendocrine systems (hypothalamiclymphoid-thyroid regulatory axis) has been postulated, since TRH increase GPBtsh expression in lymphocyte (Wang et al 1997). Furthermore, binding sites for TSH, as also for thyrostimulin, have been described in a variety of extrathyroidal tissues, including lymphocytes, adipocytes, and testicular and adrenal tissues (Pekonen & Weintraub 1978, Davies et al 1987. One of the tissues of interest is the testis, where both ligand and receptor (Feng et al 1993, Montagne et al 1999, Kumar et al 2000 co-localize.…”

Antibody-induced modulation of TSH receptor post-translational processing

“…FRTL-5 cells, a rat thyroid cell line (Ambesi-Impiombato et al 1980), were maintained as previously described (Davies et al 1987). Monoclonal TSHR-Abs Mount Sinai-1 (MS-1), 9F4, thyroid antibody (TAb)-8, 7G10, TAb-6, and TAb-16 are Armenian hamster IgG 2 mAbs (Ando et al 2002(Ando et al , 2004a.…”