Studies on bovine granulosa cells in culture
This study includes investigations into bovine granulosa cell differentiation, the response of these cells to gonadotrophin (follicle-stimulating hormone (FSH), luteinizing hormone (LH) and pregnant mares' serum gonadotrophin (PMSG)) stimulation, and the neutralizing capacity of a monoclonal antibody to PMSG (APMSG) on the response of gonadotrophin-stimulated bovine granulosa cells using a serum-free culture system. The parameters measured were cell number (mug DNA), cytoplasmic:nuclear ratio (mug protein/mug DNA), cell size (mum diameter) and cell steroidogenesis (progesterone, ng/mug DNA; oestradiol-17beta, pg/mug DNA). The following conclusions were reached. Bovine granulosa cells differentiate into luteal cells when they are cultured with gonadotrophins for a period of 4 days. Progesterone production of granulosa cells is related to the size of granulosa cells. Differentiated granulosa cells produce higher levels of progesterone than undifferentiated granulosa cells, FSH, LH and PMSG stimulate progesterone production by granulosa cells in a dose dependent manner. Similar stimulatory effects of gonadotrophins on cytoplasmic:nuclear ratio were observed. Gonadotrophins (FSH, LH and PMSG) have qualitatively similar effects on the differentiation of bovine granulosa cells in vitro. The response of bovine granulosa cells to gonadotrophin stimulation depends on the genotype form which they are derived. The stimulatory effects of PMSG, but not those of FSH or LH, on the progesterone production and protein content of granulosa cells are neutralised by APMSG. Granulosa cells in culture can be used as a bioassay system to test the relative potencies of gonadotrophin preparations and to study the neutralising capacity and specificity of APMSG preparations.