Immunolocalization of Melatonin and Follicle-Stimulating Hormone Receptors in Caprine Ovaries and their Effects During in vitro Development of Isolated Pre-Antral Follicles

Contents The expression of melatonin type 1 (MT1) and FSH (FSHR) receptors in caprine ovaries and the effects of these hormones on the in vitro development of isolated pre-antral follicles were evaluated. Follicles (200m) were cultured for 12days in -MEM (control) or melatonin (100 or 1000pg/ml) or sequential melatonin medium (100pg/ml: from day 0 to day 6; 1000pg/ml: from day 6 to day 12; experiment 1) and in control or sequential FSH (100ng/ml from day 0 to day 6; 500ng/ml from day 6 to day 12) or sequential melatonin or this latter plus sequential FSH (experiment 2). MT1 and FSHR expressions were observed in granulosa cells from secondary and antral follicles. The oocytes from primordial and primary follicles also express FSHR. Sequential melatonin increased the percentage of normal follicles and oocyte recovery compared with the control or melatonin (1000pg/ml) at day 12. In experiment 2, all the treatments increased the normal follicles and growth compared with the control. In conclusion, this study demonstrated the presence of MT1 and FSHR in caprine ovaries. The addition of increased concentrations of melatonin (sequential medium) or FSH can be used to promote the in vitro development of caprine pre-antral follicles.