EFFECT OF TSH ON cAMP AND cGMP LEVELS IN THYROID CANCERS, ADENOMAS AND NORMAL HUMAN THYROID TISSUE

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Abstract
The effect of TSH [thyroid stimulating hormone] (50 mU/ml) alone or in combination with theophylline (10 mM) on the c[cyclic]AMP level in human thyroid tissue after a 10 min incubation was studied in 8 normal tissues, 7 adenomas and 10 thyroid cancers (8 differentiated and 1 anaplastic). The lack of responsiveness to TSH in the 2 anaplastic carcinomas studied, as well as in 4 cases among the 8 differentiated cancers studies was shown. In thyroid adenomas, the cAMP increase in response to TSH was close to that observed in normal tissues. In these adenomas, the mean basal cAMP level (0.43 .+-. 0.07 pmol/mg tissue) was not statistically different from that in normal tissues (0.36 .+-. 0.06), while in thyroid cancers the mean basal cAMP level (0.93 .+-. 0.26) was significantly greater than than in normal tissues (P < 0.05). The cGMP level was measured in the same conditions in 7 normal thyroid tissues and 8 thyroid cancers (7 differentiated and 1 anaplastic). The mean basal cGMP level in these cancers (9 .+-. 1 fmol/mg tissue) was not statistically different from that in normal tissues (12 .+-. 2). In response to TSH, no increase of cGMP was observed in cancers or normal tissues. The disorders of hormone synthesis previously seen in human thyroid cancers and in some cases of differentiated carcinomas.