effects of nonpulsatile gnrh agonist administration on ovaries of immature rats

introduction: pulsatile injection of gnrh in hypothalamic amenorrhea is known to result in ovulation. the aim of this research was to study the effect of non pulsatile gnrh agonist administration on the ovaries of immature rats. material and methods: in this research the immature rats was divided to 7,17 and 27 daysand each were subdivided to four subgroups. subcutaneous injection every 12 hours for 3 consecutivedays was carried out, and mature rats were used as a second control group. after spinal transetion, the ovaries were excised and processed for histolgical study using 5µm serial section. results: the results were as follows, 1- in the 7 day rats high dose injection significantly decreasedthe number of vesicular follicles compared to control group. no significant difference was observed in the other groups with the same dosage. 2- in the 17 day rats high dose injection significantly increased the number of primary follicles but decreased the primary and secondary vesicular follicles. in contrast,the middle dose in comparison to high dose administration resulted in significant increase in the number of primary and secondary vesicular follicles, but not the primary follicles. low doseadministration in the same group, showed no significant change compared with the control group.3- in the 27 day group the high dose did not result in any change in the number of primary follicles andvesicular follicles, but decreased the number of secondary vesicular and graffian follicles, and the number of corpus luteums obviously increased, similar to middle dose administration. this was incontrast to high dose which the number of secondary vesicular and graffian follicles increased and the number of corpus luteum, as compared to former group also significantly increased. 4- comparisonbetween immature 27 day and 60 day mature rats showed decrease in the primary follicles andvesicular follicles while increase in the number of secondary and graffian follicles and corpus luteum,but the middle dose administration compared to mature rats showed almost a similar pattern. conclusion: finally it can be concluded that the non pulsatile administration can result in maturation of follicle and may be similar to the mature group. high dose stimulates the maturation of primary follicles but suppresses maturation of graffian follicles and low dose administration dose not have any effect on maturation of follicles.