The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
 
 
 

Thyrotropin dependent and independent thyroid cell lines selected from FRTL-5 derived tumors grown in nude mice.

FRTL-5 cells were used to set up a thyroid tumor model system in C3H nu/nu mice. FRTL-5 tumors could be grown in nude mice provided serum TSH levels were elevated. Persistent TSH elevation was obtained by administration of Na131I, rendering the mice hypothyroid. After 4 weeks FRTL-5 cells were injected sc resulting in tumor growth within 2 weeks in eight out of eight mice. Although the tumors showed an apparently undifferentiated histology, lacking normal follicular structures, they were functional since the tumors were capable of concentrating [131]iodine, as demonstrated by nuclear imaging. From one of the tumors a new cell line was isolated (FRTL-5/T) that, like the parental FRTL-5 cell line, was TSH dependent for growth. In a control group of six euthyroid nude mice FRTL-5 tumor growth could not be obtained with one exception. After 3 months one animal developed a small tumor that grew rapidly thereafter. This tumor was easily transplantable in other euthyroid nude mice, showed an undifferentiated histology, and was nonfunctional, as it could not concentrate [131]iodine. From this tumor two cell lines were derived: one cultured in the presence of TSH (FRTL-5/TP) and one in the absence of TSH (FRTL-5/TA). Both cell lines were found to be TSH independent for growth. The cell lines were analyzed for TSH responsive functions and TSH receptor expression. Responsiveness to TSH in FRTL-5/T and the parental FRTL-5 cell line were similar for most thyroid specific functions tested. However, FRTL-5/T was less sensitive than FRTL-5 for TSH induced [3H]thymidine incorporation. Both cell lines had two classes of TSH binding sites with high and low affinity respectively, as determined by Scatchard analysis. FRTL-5/TP and FRTL-5/TA were both able to grow in TSH free medium and were nonresponsive to TSH in vitro, as tested for [3H]thymidine and [3H]uridine incorporation, iodine uptake, thyroglobulin iodination, and thyroglobulin secretion. This correlated with an approximately 100-fold decreased number of TSH binding sites compared to FRTL-5. The latter was caused by a complete absence of low affinity binding sites, whereas high affinity receptors were still detectable. The FRTL-5/TA cell line was the least differentiated one as thyroglobulin mRNA was detectable in only minute amounts and thyroid peroxidase expression could not be measured. These in vivo selected FRTL-5 cell lines offer a suitable model to investigate several aspects of TSH responsiveness, including signal transduction and postreceptor events, thyroid differentiation, and thyroid tumorigenesis.[1]

References

  1. Thyrotropin dependent and independent thyroid cell lines selected from FRTL-5 derived tumors grown in nude mice. Ossendorp, F.A., Bruning, P.F., Schuuring, E.M., Van Den Brink, J.A., van der Heide, D., De Vijlder, J.J., De Bruin, T.W. Endocrinology (1990) [Pubmed]
 
WikiGenes - Universities