The effects of formulation on the immunostimulatory activity of dihydroheptaprenol

Holstein steer calves received a single injection of Miglyol (Sasol Chemical Industries, Ltd.) subcutaneously as a placebo, dihydroheptaprenol (DHP) (4 mg/kg) emulsified with lecithin subcutaneously, DHP in solution in Miglyol (4 mg/kg) subcutaneously, or DHP in solution in Miglyol (4 mg/kg) intranasally. The DHP emulsified in lecithin emulsion administered subcutaneously caused a substantial increase in body temperature, total leukocyte count, total neutrophil count, neutrophil cytochrome-c reduction, and neutrophil iodination 24 hours after administration and, for some of the parameters, at 48 hours. The DHP formulation in Miglyol did not have any of these effects when administered subcutaneously or intranasally. The carrier and formulation of DHP apparently have major effects on the biologic activity of DHP.