Effect of heparin on leukocyte response to hydrocortisone injections

¹ Research Service, Wood Veterans Administration Center, and Department of Physiology, Marquette University School of Medicine, Milwaukee, Wisconsin

A subcutaneous injection of heparin (100 IU and 500 IU/100 g body wt.) produced a panleukocytosis in rats. The lymphocyte response was greater with 500 than with 100 IU/100 g body wt. The leukocyte count returned toward control levels 8 hr after the injection. The magnitude of the leukocyte response to heparin was unaffected by the blood sampling site, the sex of the animal, or the preparation of heparin used to elicit the response. Hydrocortisone (3 mg/100 g body wt.) produced a lymphopenia 4 and 8 hr after its subcutaneous injection. It produced no significant change in the neutrophil count at either of these times. When the two drugs were given to rats simultaneously, heparin antagonized the effect of hydrocortisone on the lymphocyte count and hydrocortisone inhibited the effect of heparin on the neutrophil count.