title: Primary B cell development is impaired in mice with defects of the pituitary/thyroid axis.
abstract: There has been considerable speculation that hormones produced in the anterior pituitary gland act as positive regulators of primary B cell development in the bone marrow. In order to identify endocrine factors that have such a role, B cell differentiation was examined in a panel of mice with genetic mutations that result in compromised production of one or more anterior pituitary hormones. This analysis demonstrated that the frequency of B lineage cells is significantly reduced in the dwarf and hypothyroid strains of mice, which have defects in the pituitary/thyroid axis, and that the production of normal numbers of pre-B cells is particularly dependent upon thyroid hormones. B cell development was normal in Little and IGF-I knockout animals, which have defects in the production of growth hormone and/or insulin-like growth factor I. The dependence of B lymphopoiesis on thyroid hormones appeared to be specific for that lineage, as myelopoiesis and thymopoiesis were normal in dwarf and hypothyroid mice. In addition to describing a specific endocrine hormone involved in the regulation of B cell development, these data provide evidence that normal production of bone marrow B lineage cells is dependent on extramedullary signals.
authors.affiliation: Department of Pathology and Laboratory Medicine and The Jonsson Comprehensive Cancer Center, School of Medicine, University of California, Los Angeles 90095, USA.
authors.forename: E
authors.initials: E
authors.lastname: Montecino-Rodriguez
authors.forename: R G
authors.initials: RG
authors.lastname: Clark
authors.forename: L
authors.initials: L
authors.lastname: Powell-Braxton
authors.forename: K
authors.initials: K
authors.lastname: Dorshkind
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D001402:B-Lymphocytes / Q000166:cytology* / Q000502:physiology; D051927:CD24 Antigen; D002454:Cell Differentiation / Q000502:physiology; D005434:Flow Cytometry; D008562:Membrane Glycoproteins; D051379:Mice; D008817:Mice, Mutant Strains; D010902:Pituitary Gland / Q000502:physiology*; D010907:Pituitary Hormones / Q000502:physiology*; D013961:Thyroid Gland / Q000502:physiology*
chemical_list: D015703:Antigens, CD; D051927:CD24 Antigen; C497890:Cd24a protein, mouse; D008562:Membrane Glycoproteins; D010907:Pituitary Hormones