title: Plasma ghrelin and desacyl ghrelin concentrations in renal failure.
abstract: Ghrelin is a novel hormone that possesses growth hormone (GH)-releasing, cardiovascular, and metabolic activities. Ghrelin is a unique acylated polypeptide, and the naked peptide, desacyl ghrelin, does not have the activity. This study examines plasma ghrelin concentrations in 41 patients with mild to severe renal diseases. Two kinds of radioimmunoassays were used: amino-terminal immunoreactivity represents ghrelin alone (N-IR), and carboxyl-terminal immunoreactivity corresponds to the sum of both ghrelin and desacyl ghrelin (C-IR). In all subjects, the plasma N-IR was much smaller than the C-IR, indicating that desacyl ghrelin predominates over ghrelin in the circulation. The plasma C-IR, but not N-IR, was significantly correlated with the serum creatinine level and was increased 2.8-fold in patients with end-stage renal disease compared with those in patients with normal renal function. The plasma GH concentration was significantly correlated with the plasma N-IR and the C-IR, as well as with the serum creatinine level. Bilateral nephrectomy in mice caused marked increase in the plasma C-IR without significant changes in the local C-IR and ghrelin mRNA level in the stomach, which is the main site of ghrelin production. These findings suggest that circulating ghrelin concentrations play a role in the regulation of blood GH concentrations and that the kidney is an important site for clearance and/or degradation of desacyl ghrelin. Furthermore, elevation of blood GH levels in renal failure seems to be caused by a mechanism other than alteration in the circulating ghrelin concentration.
authors.affiliation: Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yoshimoto
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Mori
authors.forename: Akira
authors.initials: A
authors.lastname: Sugawara
authors.forename: Masashi
authors.initials: M
authors.lastname: Mukoyama
authors.forename: Kensei
authors.initials: K
authors.lastname: Yahata
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Suganami
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Takaya
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hosoda
authors.forename: Masayasu
authors.initials: M
authors.lastname: Kojima
authors.forename: Kenji
authors.initials: K
authors.lastname: Kangawa
authors.forename: Kazuwa
authors.initials: K
authors.lastname: Nakao
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D005260:Female; D054439:Ghrelin; D019382:Human Growth Hormone / Q000097:blood; D006801:Humans; D015592:Immunoradiometric Assay; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000503:physiopathology / Q000628:therapy; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008875:Middle Aged; D009392:Nephrectomy; D009994:Osmolar Concentration; D036361:Peptide Hormones / Q000097:blood* / Q000652:urine; D006435:Renal Dialysis; D012720:Severity of Illness Index
chemical_list: D054439:Ghrelin; D036361:Peptide Hormones; C422650:ghrelin, des-n-octanoyl; D019382:Human Growth Hormone