Screening the foods of an endangered parrot, the kakapo (Strigops habroptilus), for oestrogenic activity using a recombinant yeast bioassay

Abstract

In recent years the possibility of environmental oestrogens affecting thereproduction of vertebrates has become an issue of both public and scientificinterest. Although the significance of such chemicals remains controversialthere is clear evidence that, in some contexts, environmental oestrogens caninfluence the fertility of vertebrates. Highly endangered species represent asituation in which even modest reductions in the fertility of key individualsmay have implications for the survival of the entire species. This paperreports the screening of both natural and supplementary foods of the kakapo(Strigops habroptilus), a critically endangered NewZealand nocturnal parrot, for oestrogenic activity using a recombinant yeastbased bioassay. Low levels of oestrogenic activity were detected in one of the&lsquo;chick-raising&rsquo; foods, but no oestrogenic activity was detected inthe adult supplementary foods. The oestrogenicity of a range of phytochemicalspossibly associated with the kakapo natural diet was also examined. Two suchphytochemicals, podocarpic acid and its reduced derivative podocarpinol,showed weak oestro-genic activity (approximately 10<emph type="7">-6 and 10 <emph type="7">-4 of theactivity of 17-b -oestradiol, respectively).