Circulating ghrelin levels of visceral obese men are not modified by a short-term treatment with very low doses of GH replacement.
Ghrelin, the endogenous ligand for the GH secretagogue-receptor (GHS-R), in addition to its GH-releasing action, has orexigenic and adipogenic properties. These characteristics make ghrelin a potential hormone involved in the pathogenesis of obesity. Ghrelin levels are decreased in obese humans and it is unknown whether this decrease is responsible for the blunted GH secretion reported in visceral obesity. Since only few data are available on the potential feedback regulation by GH on systemic ghrelin concentrations, it remains to be established whether the correction of circulating GH concentrations in obese individuals affects ghrelin concentrations. To answer this question, we measured plasma ghrelin levels after a week of administration of low doses of recombinant human GH (rhGH) in a randomized, double-blind, placebo (PL)-controlled trial. This study was originally designed to evaluate the effects of GH replacement on lipid kinetics in visceral obese men. Six adult men with abdominal/visceral obesity (age 42+/-3 yr, body weight 107 +/- 10 kg, BMI 33 +/- 1 kg/m2, waist circumference 111 +/- 3 cm, mean +/- SE) were evaluated in the basal state (BS) and after one week of treatment with subcutaneous bedtime injections of either PL, 2.5 (GH2.5) or 3.3 (GH3.3) pg/kg/die of rhGH. In comparison to BS either PL, GH2.5 or GH3.3 did not significantly modify circulating ghrelin concentrations (p = 0.77). In contrast, a significant increase of serum GH (p = 0.0028), IGF-I (p = 0.0033) and whole body rate of lipolysis (p = 0.038, GH2.5; p = 0.009, GH3.3) occurred, in comparison to BS or PL, after GH2.5 and GH3.3, without differences between the two treatments. These data demonstrate that in abdominal/visceral obese men a short-term treatment with very low doses of rhGH replacement, sufficient to augment the rate of lipolysis, do not modify circulating ghrelin levels.
Murdolo
G
G
Department of Internal Medicine, Section of Internal Medicine, Endocrine and Metabolic Sciences, University of Perugia, Perugia, Italy. murdolo@dimisem.med.unipg.it
Lucidi
P
P
Di Loreto
C
C
Parlanti
N
N
De Cicco
A
A
Fanelli
C
C
Perriello
G
G
Mughetti
D
D
Pippi
R
R
Brozzetti
A
A
Santeusanio
F
F
De Feo
P
P
D000328:Adult; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D054439:Ghrelin; D019382:Human Growth Hormone / Q000008:administration & dosage*; D006801:Humans; D007279:Injections, Subcutaneous; D008066:Lipolysis; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000188:drug therapy* / Q000378:metabolism; D036361:Peptide Hormones / Q000097:blood*; D014781:Viscera
D054439:Ghrelin; D036361:Peptide Hormones; D019382:Human Growth Hormone