Effects of diet, exercise and anorexigenic drugs on serum thyroid hormones.

The serum levels of T4, T3 and rT3 were estimated in moderately obese women treated with diet (900-1000 kcal) and 4 h of exercise, supplemented with placebo or anorexigenic drugs (phenmetrazine, phentermine and mazindol). After 12 days of treatment, no change in serum T4 occurred in the placebo group (-4%), while in the groups with anorexigenic drugs a significant rise of T4 was observed (phenmetrazine +33%, phentermine +14% and mazindol +20%). Serum T3 decreased significantly in the placebo and the anorexigenic groups to a similar extent (from -21% to -27%) with the exception of mazindol.