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Pertubations in myocardial mitochondrial bioenergetics by the aqueous corm extract of Hypoxis hemerrocallidea [African Potato;APE] in a rat model of type I diabetes mellitus
Author(s) -
Zungu Makhosazane,
Jawuza Nelisiwe Mangazile
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.660.9
Subject(s) - oxidative phosphorylation , mitochondrion , bioenergetics , medicine , type 2 diabetes mellitus , chemistry , endocrinology , diabetes mellitus , oligomycin , pyruvate dehydrogenase complex , pharmacology , biochemistry , atpase , enzyme
To study the effects of APE on myocardial mitochondrial bioenergetics, Type I diabetes mellitus was induced in male Sprague Dawley rats by a single streptozotocin (STZ) injection (60 mg/kg.bw; i.p). After 3 weeks rats were orally treated (every third day) with distilled water (3ml/kg.bw) or APE (30 mg/kg. bw) for 5 weeks. The vehicle group was given citrate buffer followed by APE treatment. Heart mitochondrial functional parameters were measured using a Clark‐type oxygen electrode and employing a combination of malate (M), palmitoyl‐L‐carnitine (CP), pyruvate (P) and succinate as oxidative substrates. ADP/O ratio was increased in the diabetic group in the presence of MCP and M+P. APE treatment reduced ADP/O ratio and rate of ADP phosphorylation (MCP and succinate as substrates). Treatment of the diabetic group with APE attenuated the ADP/O ratio (for all substrates used) and decreased ADP phosphorylation rate (MCP as substrates), while it increased oligomycin‐insensitive proton leak and state 4 respiration (succinate as substrate). Our results demonstrate that APE inhibits rat heart mitochondrial efficiency and uncouples oxidative phosphorylation in a substrate‐dependent fashion and may help explain observed cardiac dysfunction associated with usage of this medicinal plant. South African Medical Research Council, South African National Research Foundation.