Enhanced expression of hexokinase I mRNA in male rat tissues by homobrassinolide.

The subchronic effect of the plant hormone homobrassinolide, a dietary constituent of vegetables and green leaves, was investigated in male albino Wistar strain rats. Blood sugar and serum insulin content, tissue hexokinase enzyme activity, and mRNA expression were studied using homobrassinolide administered orally by gavage at 50 μg (333 μg/kg body weight) for 15 consecutive days. Selected tissue responses were determined at 16 days post administration in control and experimental animals employing established methods. Homobrassinolide reduced the circulating blood sugar and increased the serum insulin level significantly. Hexokinase activity in the brain, heart, liver, kidney, and testis of experimental rats was found elevated. Hexokinase mRNA expression detected employing polymerase chain reaction (PCR) technique was found significantly increased in the brain and liver compared to other tissues. It is suggested that this plant hormone is a transcriptional activator of hexokinase gene, promoting enhanced hexokinase mRNA synthesis in vivo in rat tissues.