The first employed substances, called aromatase inhibitors, which prevent the formation of oestradiol by the developing embryo. This technique simply acts as a model in which, theoretically, all the factors which control testicular differentiation and development are presented to the developing genetic female embryo. Obviously this procedure would not be a practical approach on a commercial scale. The use of the factors may be a viable option on a commercial scale. Outcomes It was found that transformation of genetic females to males could be achieved using aromatase inhibitors.
Aromatase inhibitors are substances which prevent the formation of the female hormone oestradiol.
However, at the concentrations used in these experiments the aromatase inhibitors appeared to have toxic effect leading to high embryonic mortality. This apparent toxicity was reduced when a cross-bred layer strain was used. On gross post mortem examination these transformed genetic females had two apparently normal looking testicles and plasma testosterone concentrations equivalent to genetic males, suggesting that the testes were functioning as normal male testes. Implications Clearly more work is required to modify the procedures to achieve a high rate of transformation. However, with the advent of multi-egg injectors it is now possible to manipulate developing embryos on a large scale.