Administration of ghrelin to young uraemic rats increases food intake transiently, stimulates growth hormone secretion and does not improve longitudinal growth.
BACKGROUND
Ghrelin administration stimulates appetite and growth hormone (GH) secretion. Whether these effects are preserved in young individuals with chronic renal failure (CRF) and their potential benefit on growth is questioned.


METHODS
Three experiments were performed in subtotally nephrectomized young rats (Nx). (i) Food intake was monitored in CRF rats receiving saline intraperitoneally or a ghrelin dose (30 nmol) shown to increase food intake over 2 and 24 h in rats with normal renal function. (ii) Plasma levels of GH were measured after a dose of intravenous ghrelin (3 nmol) was given to three groups of five rats each: Nx, sham-operated fed ad libitum (SAL) and sham-operated pair-fed with Nx (SPF). (iii) Growth of Nx rats treated with intraperitoneal ghrelin (3 nmol) for 7 days (Nx-Ghr) was compared with that of SAL and Nx groups receiving saline (n=8-10 per group).


RESULTS
In CRF rats, the dose of 30 nmol of ghrelin increased food consumption for 2 h (1.3+/-0.2 g vs 0.5+/-0.2 g, P<0.05) but not 24-h food intake (12.5+/-0.6 g vs 12.2+/-0.5 g). Ghrelin (3 nmol) increased plasma levels of GH, which were maximal 10 min after injection, no differences being observed among groups (SAL: 666.2+/-104.6 ng/ml; Nx: 691.6+/-90.7 ng/ml; SPF: 577.8+/-125.4 ng/ml). Return to basal GH levels was delayed in Nx. Ghrelin did not improve body length and weight gains, longitudinal bone growth rate or food intake in the Nx-Ghr group.


CONCLUSIONS
In young uraemic rats, ghrelin increases appetite but not 24-h food intake, stimulates GH secretion and does not improve growth.
Alvarez-García
Oscar
O
Universidad de Oviedo, and Hospital Universitario Central de Asturias, Spain.
García-López
Enrique
E
Rodríguez
Julián
J
Gil-Peña
Helena
H
Molinos
Inés
I
Carbajo-Pérez
Eduardo
E
Santos
Fernando
F
D000818:Animals; D001066:Appetite / Q000187:drug effects / Q000502:physiology; D001846:Bone Development / Q000187:drug effects* / Q000502:physiology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects* / Q000502:physiology; D054439:Ghrelin; D013006:Growth Hormone / Q000097:blood / Q000187:drug effects / Q000378:metabolism*; D007274:Injections, Intraperitoneal; D007275:Injections, Intravenous; D007676:Kidney Failure, Chronic / Q000097:blood / Q000503:physiopathology; D008297:Male; D009392:Nephrectomy; D036361:Peptide Hormones / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014511:Uremia / Q000097:blood / Q000503:physiopathology*
D054439:Ghrelin; D036361:Peptide Hormones; D013006:Growth Hormone