Analysis of thymidine kinase activity and glucocorticoid-binding capacity in the thymuses of healthy and tumor-bearing chickens.
Thymidine kinase activity in the lymphoid organs of healthy and tumor-bearing chickens was studied after hydrocortisone or dexamethasone treatment. Glucocorticoid hormones (10 mg/100 g body wt) administered twice in 48 hours resulted in an 80% decrease in thymidine kinase activity in the thymuses of healthy chickens, whereas birds with transplantable MC 29 chicken hepatoma failed to respond to the hormones. In the bursae of Fabricius of healthy or tumor-bearing chickens, thymidine kinase activity did not change considerably after administration of hydrocortisone or dexamethasone. The steroid-binding capacity in cellfree systems prepared from thymuses of tumor-bearing birds was significantly decreased. Thus the difference in steroid-binding capacity between thymuses of healthy and tumor-bearing chickens correlated well with, and could account for, the failure of hydrocortisone and dexamethasone to reduce the thymidine kinase level in tumor-bearing birds.
D000818:Animals; D002060:Bursa of Fabricius / Q000378:metabolism; D002645:Chickens; D003907:Dexamethasone / Q000494:pharmacology; D006854:Hydrocortisone / Q000494:pharmacology; D066298:In Vitro Techniques; D009374:Neoplasms, Experimental / Q000188:drug therapy / Q000378:metabolism*; D011965:Receptors, Glucocorticoid; D011987:Receptors, Steroid; D013154:Spleen / Q000378:metabolism; D013937:Thymidine Kinase / Q000378:metabolism*; D013950:Thymus Gland / Q000378:metabolism*
D011965:Receptors, Glucocorticoid; D011987:Receptors, Steroid; D003907:Dexamethasone; D013937:Thymidine Kinase; D006854:Hydrocortisone