[The denydroepiandrosterone sulfate thyroid activation through the mu-opioid receptors under cold influences]

Denydroepiandrosterone-sulfate (DHEAS) effects on total thyroxine (tT4), total triiodothyronine (tT3), and free thyroxine (tT4) levels were studied in male rats under single or repeated (for 19 days, 1 hr a day) cold influences, as well as participation of mu-opioid receptor effects in DHEAS (30 mg/kg). It was shown that the increased tT4 and tT3 levels under repeated cold influences were more obvious after DHEAS injections. The opioid antagonist naltrexone in the dose 0.1 mg/kg reversed the DHEAS effect. These data suggest involvement of mu-opioid receptors in that thyroid activation. Under a single cold influence DHEAS did not produce the effects at tT4, or tT3 levels, and the action of mu-opioid receptor blocker in this situation was not manifested. The fT4 levels were obviously increased both under repeated or single cold influences, but the DHEAS and naltrexone actions were absent.