Peripheral blood leukocyte alterations in mice induced by a hemoregulatory pentapeptide (HP 5b)

The effects of different doses of a synthetic hemoregulatory pentapeptide, analoguous to an inhibitory factor associated with human granulocytes, on the numbers of peripheral blood leukocytes have been investigated in female C 3H mice. Following single injections as well as continuous infusion for 6 days, the numbers of granulocytes in peripheral blood were reduced to about one half of the normal. Maximal effect with single injection was seen with 120 μg (10 −3 M), while 1.2 mg (10 −4 M) as one dose only had a slight, temporary effect on the granulocyte numbers in peripheral blood. Upon continuous infusion of 14 μg/h (