Pituitary and thyroid hormone responses of heifers after ferulic acid administration.

I evaluated effects of ferulic acid on concentrations of endocrine hormones of eight Holstein heifers. Cattle were fitted with indwelling jugular cannulae 24 h before experimentation. After control blood samples were taken, animals were assigned randomly to groups of four and infused with 100 or 500 mg of ferulic acid. Prolactin, growth hormone, luteinizing hormone, and thyroid hormones were measured in sera from blood samples. Blood sampling or ethanol infusion did not affect serum concentrations of prolactin. Serum prolactin was elevated 5 min after infusion of ferulic acid. Peak serum prolactin concentrations were 15 min after 100 mg of ferulic acid and between 10 and 30 min after 500 mg ferulic acid. Prolactin remained high until 120 min post drug administration. Control bleeding and ethanol administration did not alter serum growth hormone concentrations. Serum growth hormone concentrations were elevated slightly by ferulic acid. The increase was 5 min after drug administration. Baseline concentrations were established 60 to 90 min after administration. Ferulic acid did not affect luteinizing hormone or thyroid hormones. Ferulic acid, a constituent of corn and wheat germ, may affect release of pituitary hormones in cattle.