Concomitant expression of receptor subtype and isopeptide of endothelin by human adrenal gland.
We studied whether specific receptors for endothelin (ET) isopeptide exist in human aldosterone-producing adenoma and normal adrenal cortex, and whether ET isopeptides are produced by human adrenal gland. Competitive binding studies using [125I]ET-1 as a radioligand revealed the presence of a single class of high-affinity binding sites for ET-1 with the apparent KD of 70 +/- 31 pM and Bmax of 226 +/- 139 fmol/mg protein in adenoma membranes almost comparable to those in adjacent normal cortex. The apparent Ki for ET-2 and ET-3 were 89 +/- 33 pM and 82 +/- 16 pM, respectively. Northern blot analysis of poly(A)+ RNA of adenoma and adjacent normal cortex using cDNAs for ET receptor subtype (ETA, ETB) and ET isopeptide (ET-1, ET-3) as probes revealed that ETA and ETB receptors as well as ET isopeptides (preproET-1, preproET-3) are concomitantly expressed in both tissues. Our data demonstrate for the first time that ET receptor subtype (ETA and ETB) and ET isopeptide (ET-1 and ET-3) are concomitantly expressed by human adrenal cortex, suggesting the potential role of ETs as a local mediator in human adrenal gland.
Second Department of Internal Medicine, Tokyo Medical and Dental University, Japan.
T
T
Imai
Y
Y
Hirata
S
S
Eguchi
K
K
Kanno
K
K
Ohta
T
T
Emori
A
A
Sakamoto
M
M
Yanagisawa
T
T
Masaki
F
F
Marumo
D000236:Adenoma / Q000378:metabolism*; D000302:Adrenal Cortex / Q000378:metabolism*; D000306:Adrenal Cortex Neoplasms / Q000378:metabolism*; D000311:Adrenal Glands / Q000378:metabolism*; D001667:Binding, Competitive; D015152:Blotting, Northern; D003001:Cloning, Molecular; D016232:Endothelins / Q000096:biosynthesis / Q000378:metabolism*; D006801:Humans; D007536:Isomerism; D007700:Kinetics; D011061:Poly A / Q000235:genetics / Q000302:isolation & purification; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D017466:Receptors, Endothelin
D016232:Endothelins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D017466:Receptors, Endothelin; D011061:Poly A; D012313:RNA