Binding sites for interleukin-6 in the anterior pituitary gland.
Interleukin-6 (IL-6) binding site in the rat anterior pituitary gland was characterized using radioiodinated human recombinant (hr) IL-6. Results showed that the anterior pituitary gland contained 170 binding sites per cell of a single class with a dissociation constant of 2.7 x 10(-9) M. The binding of 125I-hrIL-6 to the rat anterior pituitary gland was competitively inhibited by unlabeled hrIL-6, but not by hrIL-1 alpha, hrIL-1 beta, hrIL-2 or hr-interferon-gamma, indicating these binding sites are specific for IL-6. We also demonstrated mouse IL-6 receptor gene expression in the rat anterior pituitary gland by Northern blot analysis. Furthermore, the IL-6 receptor was detected on human gonadotrophs by the double immunofluorescence method. Our findings demonstrate the presence and expression of IL-6 binding site in the rat anterior pituitary gland and the presence of IL-6 binding site on human gonadotrophs, suggesting the important role of IL-6 binding site in pituitary hormone release in both species.
Ohmichi
M
M
Department of Obstetrics and Gynecology, Osaka University Medical School, Japan.
Hirota
K
K
Koike
K
K
Kurachi
H
H
Ohtsuka
S
S
Matsuzaki
N
N
Yamaguchi
M
M
Miyake
A
A
Tanizawa
O
O
D000818:Animals; D001665:Binding Sites / Q000502:physiology; D015152:Blotting, Northern; D005260:Female; D005455:Fluorescent Antibody Technique; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism*; D007457:Iodine Radioisotopes; D010903:Pituitary Gland, Anterior / Q000196:embryology / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains
D015850:Interleukin-6; D007457:Iodine Radioisotopes; D012333:RNA, Messenger