Dual expression of p80 type I and p68 type II interleukin-I receptors on anterior pituitary cells synthesizing growth hormone.
Interleukin-1 alpha (IL-1 alpha) and IL-1 beta bind to either the p80 type I IL-1 receptor (IL-1RI) or the p68 type II IL-1R (IL-1RII) on both T and B lymphocytes. We and others have previously shown that the anterior pituitary gland also has specific high affinity binding sites for IL-1 alpha (Kd = approximately 1 nM) and expresses transcripts for both isoforms of the IL-1R. However, the identity of cells in the anterior pituitary gland that express the IL-1R and whether different populations of adenohypophyseal cells express different isoforms of the IL-1R remain unknown. Here we have used a combination of immunohistochemistry and histochemistry to localize IL-1RI and IL-1RII to specific target cells in the mouse anterior pituitary gland. Perfusion-fixed, paraffin-embedded sections of anterior pituitary gland were immunolabeled with well characterized monoclonal antibodies to either IL-1RI or IL-1RII and counterstained using a modified Gomori's method to document acidophils and basophils. Immunolabeling demonstrated that both IL-1RI and IL-1RII were abundantly expressed on a single population of anterior pituitary gland cells and that these cells could be classified on the basis of histochemical staining as a subpopulation of acidophils. The distribution, morphology, and proportion of cells immunolabeled for IL-1RI and IL-1RII were consistent with GH-synthesizing cells. To confirm this hypothesis, a modified indirect avidin-biotin complex, sequential peroxidase/alkaline phosphatase technique was used to label anterior pituitary gland cells with antibodies to IL-1RI followed by antibodies to IL-1RII, GH, PRL, or ACTH. The IL-1RI-positive cells predominately coexpressed IL-1RII and GH, but very little, if any, PRL or ACTH. These data establish that the predominant cell population in the murine anterior pituitary gland that constitutively expresses IL-1R stain as acidophils histochemically, is round to oval with dense granular cytoplasm and eccentric nuclei, synthesizes GH, and simultaneously expresses IL-1RI and IL-1RII isoforms.
French
R A
RA
Department of Veterinary Pathobiology, University of Illinois, Urbana-Champaign 61801, USA.
Zachary
J F
JF
Dantzer
R
R
Frawley
L S
LS
Chizzonite
R
R
Parnet
P
P
Kelley
K W
KW
D000818:Animals; D002460:Cell Line; D005260:Female; D013006:Growth Hormone / Q000096:biosynthesis*; D007150:Immunohistochemistry; D007375:Interleukin-1 / Q000378:metabolism*; D007536:Isomerism; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000378:metabolism*; D017472:Receptors, Interleukin-1 / Q000378:metabolism*
D007375:Interleukin-1; D017472:Receptors, Interleukin-1; D013006:Growth Hormone