Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.6.1.1 (adenylate cyclase)
 19,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although an autoimmune pathogenesis for non toxic goiter has been suggested, reports concerning circulating antibodies to TSH receptor structures have been conflicting. Intra thyroid lymphocytes, capable of secreting IgG, have been shown to be involved in the pathogenesis of Graves' and Hashimoto's diseases; therefore, the ability of conditioned media obtained from intra thyroid lymphocyte culture, and of IgG purified from these media, to stimulate cAMP accumulation and [3H]-Thymidine (TdR) uptake in FRTL-5 cells was investigated. The activity of IgG produced "in vitro" was compared with that of circulating IgG. Thyroid tissue samples were obtained at surgery from 21 patients with non toxic multinodular goiter (MNG), 5 patients with active Graves' disease (GD), and from 10 normal subjects, undergoing neck surgery for non-thyroidal pathology. IgG purified from media of GD lymphocyte cultures stimulated both cAMP accumulation and [3H]-TdR in 5 out of 5 cases: all of the IgG purified from control or MNG lymphocyte culture media was not active in either assay. Circulating IgG did not affect cAMP accumulation or [3H]-TdR in any of the non toxic MNG cases: controls showed no changed at all. However, both activities represented were increased by GD IgG. Conditioned media from intra thyroid lymphocyte cultures significantly inhibited basal cAMP accumulation in 7 out of the 21 non toxic MNG samples and totally abolished the response in all GD patients. [3H]-TdR was not affected by IgG of any of the controls, but it had an inhibitory effect on 8 out of 21 non toxic MNG patients, and significantly stimulated [3H]-TdR in all GD patients. In conclusion, present data demonstrate that intra thyroid lymphocytes from non toxic MNG do not produce antibodies capable of mimicking TSH actions through the adenylate cyclase cascade. Conversely, soluble factors interacting in TSH-mediated functions of FRTL-5 cells are present in conditioned media of intra thyroid lymphocytes of GD and MNG thyroid lymphocytes of GD and MNG thyroid cultures.
 ...
PMID:Intrathyroidal lymphocytes from non toxic multinodular goiter: no evidence for production of thyroid stimulating antibodies. 198 28

The process of goitrogenesis is likely to be the consequence of an increased TSH stimulation linked to an initial reduction of circulating thyroid hormone caused by iodine deficiency (ID). Other growth factors associated to TSH may have a role in the pathogenesis of goiter. Natural history of goiter is the evolution towards nodularity and functional autonomy. This phenomenon is due to the heterogeneity of thyroid follicular cells, some of which, with an intrinsic elevated growth rate, under the stimulation of ID progress to nodule formation and hyperfunction. In multinodular goiter TSH receptor mutations activating adenylate cyclase-cAMP pathway were found. In a recent epidemiological survey it was shown that nodular goiter increased with the age, being about 1% in schoolchildren and 23% in the adults (56-75 years). Also nodular autonomy and hyperthyroidism were more frequent in the 36-75 year age group. Severe ID is also cause of endemic cretinism. In Europe minor neuropsychological impairments and cognitive deficits were described in areas of moderate ID. The exposure to a mild ID during fetal life causes minor neuropsychological damage. In conclusion, ID is responsible of goiter and its evolution towards nodularity and functional autonomy. Severe ID is also cause of endemic cretinism, while cognitive deficits and minor neuropsychological impairments were found in mild to moderate ID.
 ...
PMID:[Physiopathology of iodine deficiency]. 1005 65