title: Endogenous steroids are responsible for lactoferrin-induced myelopoiesis in mice.
abstract: Our previous study revealed that lactoferrin (LF) significantly increases mobilization of the myelocytic lineage in mice. The aim of our current investigation was to determine whether activation of the hypothalamic-pituitary-adrenal axis contributes to this phenomenon. We found that intravenous (iv) injection of LF (10 mg) caused a 48.8% increase in the circulating blood leukocyte count and increased the proportion of the myelocytic lineage (band forms, 10-fold and neutrophils, 2-fold) 24 h post injection. The content of the myelocytic lineage (myelocytes, metamyelocytes, bands and neutrophils) in bone marrow rose from 51.6 to 63.4%. In addition, administration of LF led to a decrease in total thymocyte number by 41.6%. Analogous changes in cell types and numbers in adrenalectomized mice following LF injection were minor. Mifepristone, a blocker of steroid receptors, reversed the effects of LF on leukocyte cell number and bone marrow cell composition. Finally, we showed that LF induced a rise in the serum levels of corticosterone in control but not adrenalectomized mice.We conclude that LF-induced upregulation of endogenous steroid levels is responsible for the stimulation of myelopoiesis.
authors.affiliation: Laboratory of Immunobiology, Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, PL 53-114 Wrocław, Poland. zimecki@iitd.pan.wroc.pl
authors.forename: Michał
authors.initials: M
authors.lastname: Zimecki
authors.forename: Jolanta
authors.initials: J
authors.lastname: Artym
authors.forename: Maja
authors.initials: M
authors.lastname: Kocieba
mesh_terms: D000315:Adrenalectomy; D000818:Animals; D002417:Cattle; D003345:Corticosterone / Q000009:adverse effects / Q000096:biosynthesis / Q000097:blood; D005260:Female; D007275:Injections, Intravenous; D007781:Lactoferrin / Q000008:administration & dosage / Q000494:pharmacology*; D051379:Mice; D008808:Mice, Inbred CBA; D038042:Myelopoiesis / Q000187:drug effects* / Q000502:physiology; D013256:Steroids / Q000009:adverse effects / Q000096:biosynthesis / Q000097:blood; D013950:Thymus Gland / Q000473:pathology / Q000502:physiology; D015854:Up-Regulation / Q000502:physiology
chemical_list: D013256:Steroids; D007781:Lactoferrin; D003345:Corticosterone