Effect of growth hormone on the activity of some lysosomal enzymes in neutrophilic polymorphonuclear leukocytes of hypopituitary dwarfs.

Elevated activities of beta-D-glucuronidase, myeloperoxidase, and lysozyme were found in polymorphonuclear leukocytes (PMNs) of both hypopituitary dwarfs and normal subjects after the administration of growth hormone (GH), as compared to the activities in PMNs from blood drawn immediately before the administration of GH. During in vitro incubation, GH was able to inhibit the release of lysosomal enzymes from resting PMNs. This inhibition may be one of the reasons for the elevated lysosomal enzyme activities observed in PMNs after the administration of GH. GH can also affect hexose monophosphate shunt (HMPS) activity and superoxide production by PMNs. The activity of HMPS is stimulated by GH in resting PMNs, while in PMNs incubated with zymosan the GH inhibits both HMPS and superoxide production.