Follicular development in immature Djungarian hamsters (Phodopus sungorus) and the influence of exogenous gonadotropins

Abstract

This study evaluated follicular development and oocyte growth in ovaries of immature Djungarian hamsters from 8 to 28 days of age and examined the influence of exogenous gonadotropins on follicular growth. An age-specific pattern of progressive follicular development was found, beginning with a compact, virtually undifferentiated ovary containing mostly small follicles on Day 8 postpartum and progressing to an ovary with mature preovulatory follicles at the end of the fourth week. Antral follicles not present on Day 12 were first detected on Day 16 postpartum. Follicles were sensitive to gonadotropins (GTH) by Day 12 postpartum, as indicated by the stimulation of follicular maturation by treatment with GTH. Ovulation, however, could be induced only when treatment with GTH was begun with females from Day 14 postpartum onwards. It was concluded that the injected GTH initiated and enhanced follicular growth in immature Djungarian hamsters.