title: Inhibition of bovine alpha-glucosidase by Castanospermum australe and its effect on the biochemical identification of heterozygotes for generalised glycogenosis type II (Pompe's disease) in cattle.
abstract: All 18 2-year-old Brahman bulls grazing in a paddock containing Castanospermum australe trees were diagnosed as heterozygotes for Pompe's disease by measurement of mononuclear cell alpha-glucosidase activity. However, removal of the bulls to a paddock free of C. australe and retesting 2 months later indicated that 15 were homozygous normal. An in vitro assay demonstrated that a crude aqueous extract of seeds from these C. australe trees contained a potent inhibitor of mononuclear cell alpha-glucosidase. Two Hereford steers were dosed with 0.6 g C. australe seed/kg bodyweight for 6 days. The alpha-glucosidase activity in blood mononuclear cells declined to 5% of normal within 48 h of commencement of dosing. It was therefore assumed that the bulls had consumed C. australe seeds. A means of differentiating true heterozygotes from animals consuming the toxic seed, using the ratio of plasma alpha-glucosidase activity at pH 5.6 to that at pH 3.7, is proposed.
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000139:chemically induced / Q000201:enzymology / Q000235:genetics*; D006580:Genetic Carrier Screening / Q000379:methods*; D005087:Glucan 1,4-alpha-Glucosidase / Q000037:antagonists & inhibitors*; D005959:Glucosidases / Q000037:antagonists & inhibitors*; D006008:Glycogen Storage Disease / Q000662:veterinary*; D006009:Glycogen Storage Disease Type II / Q000139:chemically induced / Q000201:enzymology / Q000235:genetics / Q000662:veterinary*; D008297:Male; D009754:Nuts / Q000009:adverse effects*; D000520:alpha-Glucosidases
chemical_list: D005959:Glucosidases; D000520:alpha-Glucosidases; D005087:Glucan 1,4-alpha-Glucosidase