Methimazole Case Study

This study has been approved by Adnan Menderes University Animal Experiments Local Ethics Committee for the ethical care and use of animals in research. All animal care and experimental procedures were in accordance with the National Institutes of Health Guide for Care and Use of Laboratory Animals 1985.
Animals
In this prospective, randomized study, 6-month old Wistar Albino female rats (210-250 g weight) and their 27 pups provided by Adnan Menderes University Medical Faculty Experimental Animal Laboratory, were used. The rats were restricted separately in plastic cages under artificial lighting from fluorescence lamps, with a 12-h light photoperiod and a 12-h dark photoperiod. The room temperature was set at 25°C constant heat and 45%-55%
This protocol and dosage of MMI administration is typically used for the production of congenitally hypothyroid rats
Vaginal smears were performed for the determination of pregnancy. When semen was detected in the vaginal smears, rats were thought to be pregnant. Pregnant rats were divided into 3 groups.
Group 1 (Methimazole-induced prenatal hypothyroidism group): Methimazole (0.025% wt/vol) was given daily in drinking water to pregnant rats from the first day of pregnancy until postnatal 21 days (E0 to P21) to generate pups with congenital hypothyroidism (n=8). Rat pups were fed with breast milk from their lactating mothers.
Group 2 (MMI-induced postnatal hypothyroidism group): The pregnant rats were fed ad libitum with water during pregnancy. Methimazole (0.025% wt/vol) was given daily in drinking water to dam rats from birth. Offspring were fed with breast milk from their mothers to generate acquired hypothroidism