The growth pattern of an animal dur

The growth pattern of an animal during treatment is a reliable
indicator in the investigation of toxic effects [44]. In humans, the loss
of weight is the most common adverse effect associated with MPH
treatment and usually disappears with time [45,46]. In rats, studies
have shown that oral MPH treatment decreases body weight in a
dose-dependent manner, as observed in neonatal rats at doses
above 50 mg/kg/day [7], as well as in adult rats in daily doses above
20 mg/kg [47]. In the present study, the MPH administrations did not
induce body weight reduction during the treatment period. It is already
described in the literature that daily doses of 5 mg/kg (via gavage) do
not induce body weight loss during development [7]. In that way, in
order to rule out the possibility of reproductive disturbances incurred
by weight loss, since the decrease in this parameter is related to changes
in sexual maturation [48,49], MPH doses that have no influence in body
weight were selected