TY - JOUR T1 - EFFECTS OF LEVOTHYROXINE ADMINISTRATION ON OVULATION RATE AND SEX HORMONE LEVELS IN PREPUBERTAL AND ADULT RATS TT - JF - MJIRI JO - MJIRI VL - 17 IS - 2 UR - http://mjiri.iums.ac.ir/article-1-706-en.html Y1 - 2003 SP - 153 EP - 157 KW - Ovulation KW - Levothyroxine KW - Hyperthyroidism KW - Prepubertal rats N2 - Thyroid gland dysfunction is associated with disorders of female reproductive functions. The aim of this study was to examine the effects of hyperthyroidism on ovulation rate and peripheral sex steroid levels in prepubertal and adult rats. Two groups of female rats aging 30 days (prepubertal rats) and 60 days (adult rats) were made hyperthyroid by oral administration of levothyroxine daily. In the two control groups (n=lO) rats with the same ages received the same volume of normal saline. After 10 days the serum levels of T3, T4, LH, FSH, estradiol and progesterone were measured by RIA technique and also sections of ovaries were prepared for histological studies. All ovarian follicles and corpora lutea were counted to estimate ovulation rate. The results indicated that serum estradiol and progesterone levels of adult hyperthyroid rats were significantly lower than those of the control group (p M3 ER -