Objective:The aim was to characterize in more details our earlier finding that purinergic agonists can induce the enzyme activities of iodothyronine deiodinases (ID) of types 2 (D2) and 3 (D3) in glial cells.

Methods: 

Astroglial cells obtained from cerebrocortical hemispheres of 2-day-old rats were grown to confluence in DMEM medium containing 10% fetal calf serum. The changes in ID activities, caused by short-term incubation (for 2–12 h) of the confluent cells in a chemically defined medium with different concentrations of purinergic effectors, without and with retinoic acid (RA, 1 micro M) pre-incubation (for 2–3 days), were quantified with the aid of our newly developed radiometric enzyme assays.

Results: 

Physiological concentrations of ATP, ADP, AMP or adenosine and of a series of their analogues caused a very marked (up to 30-fold) increase in D2 activity. D3 activity was also induced, but to a much lesser extent (3 to 7-fold increase). For the first time, the induction of iodothyronine deiodinase of type 1 (D1) by endogenous purines in these cells was also shown. Induction of ID activities was time- and concentration-dependent. Pre-incubation of cells with RA had a crucial influence on the degree of induction of D1 and D2 activities by the action of purinergic agonists (up to 42-fold increase in D2).

Conclusions: 

A new signaling pathway in the multiregulation of induction of ID activities in astroglial cells has been demonstrated. Support from the Ministry of Education of the Czech Republic (Project No. MSM0021622413), Academy of Sciences of CR (Project No. AV0Z50110509) and from the Czech Science Foundation GA CR (Grant No. 304/08/0256) is acknowledged.