Cell line bioassay for measuring FSH bioactivity in pregnant mare serum

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Cattle breeders need reliable methods to increase production of genetically valuable animals, and to improve hereditary performance traits by selection. The common approach is inducing multiple ovulation in 'donor' cows followed by transfer of the resulting embryos into the wombs of 'recipient' cows. Inducing multiple ovulation is expensive and time-consuming, and the results can be highly variable; some cows do not respond to treatment. The cheapest and least labour-intensive drug for inducing multiple ovulation is equine chorionic gonadotropin (eCG). This is a hormone that is produced by the horse placenta during pregnancy, and is purified from horse serum. Some mares produce eCG which has a higher biological activity than that produced by other mares. However, on the horse farm this variability between mares is not taken into account when eCG is collected for use as a drug for inducing multiple ovulation in cattle. This contributes to the variation in activity of batches of commercially available eCG.  Further, a large number of horses are kept for eCG production; this number can be reduced if only the best producing mares are used. To overcome these problems, a rapid method of detecting highly active eCG is required for use at the site of eCG collection. This project aims to develop such a method. We will use an ovarian cell line, which is a culture of cells that divide continually and do not die. Using genetic engineering, we can incorporate into these cells a gene that is turned on when the cells are stimulated by eCG. The higher the activity of the eCG, the greater the expression of this gene will be. Once the gene is turned on, an enzyme is produced that will cause a chemical in the incubation medium to change colour. Thus the activity of eCG can be readily detected by comparing the colour of the cells to a standardized colour chart. This will enable the Canadian pharmaceutical industry to produce a better product, and to reduce the number of horses required to make eCG. This will result in significant economic savings for Canadian cattle breeders