Induction of follicular luteinization by equine chorionic gonadotropin in cyclic guinea pigs

Abstract

Abstract:The effects of equine chorionic gonadotropin (eCG) on follicular development and ovulation in cyclic guinea pigs were investigated by histological and immunohistochemical analyses. Three groups of guinea pigs (n=12) were administrated subcutaneously with saline, 20 or 50 IU of eCG, respectively, on cyclic Day 12 (Day 1=vaginal openings). Ovaries were collected at 4 and 8 d after administration (6 animals per group each time). The eCG administration induced significant and distinct morphological changes in the ovaries, as it promoted the luteinization of granulosa cells, but not follicular development. In addition, proliferating cell nuclear antigen (PCNA) and steroidogenic acute regulatory protein (StAR) were immunolocalized specifically in luteinized follicles. Our experiments together indicate that eCG administration can induce follicular luteinization but not superovulation in guinea pigs. The eCG in cyclic guinea pigs functions similar to that of luteinizing hormone (LH), but not follicle-stimulating hormone (FSH).

Morphometric and histopathologic evaluation of the effects of cloprostenol and equine chorionic gonadotropin administration on the reproductive organs of female rats

“…Therefore, reproduction may be controlled by the lysis of the corpus luteum and by inducing a subsequent follicular phase with ovulation (27). Equine chorionic gonadotropin, which is a gonadotropic hormone produced in the chorion of pregnant mares, is widely used to obtain a large number of oocytes by the induction of superovulation in many animals (13,(18)(19)(20)(21)25). In mice, eCG and cloprostenol can promote the secretion of FSH and LH (27).…”