Glucocorticoid inhibition of growth in rats: partial reversal with the full-length ghrelin analog BIM-28125.

Abstract

Glucocorticoids are important immunosuppressive hormones; these steroids also inhibit somatic growth by decreased growth hormone (GH) secretion and induced protein catabolism. The ability of ghrelin, the endogenous ligand for the GHS-1a receptor, to increase body weight is attributed to a combination of enhanced food intake, increased gastric emptying and increased food assimilation, coupled with potent GH releasing activity. The aim of the present study was to evaluate the ability of a full-length, metabolically stabilized ghrelin agonist, BIM-28125, to reverse the dexamethasone-induced decrease of growth rate of prepubertal Sprague-Dawley male rats. Twenty-one days old rats were randomly assigned to two treatment groups. Beginning on day 23 of age, 16 animals were treated ip either with saline or DEX (40 microg/kg/day). On day 33 after birth, these two groups were further subdivided and treated sc with either vehicle or BIM-28125 (80 nmol/kg, t.i.d.). On day 47 after birth, rats were killed and trunk blood was collected for hormone determinations. DEX significantly reduced final body weight and nose-anal length; BIM-28125 increased linear growth in saline-treated rats and reversed growth inhibition in DEX-treated rats. The inhibitory effects of DEX on somatic growth was paralleled by decreased 24 h food intake (FI), decreased food efficiency (FE) and lower plasma IGF-1 levels versus vehicle-treated rats. BIM-28125 induced an increase of FI, FE and plasma IGF-1 in saline-treated rats, and reversed the inhibitory effects of DEX. These preclinical results leads to the conclusion that BIM-28125 may represent a good tool to reverse the catabolic effects induced by glucocorticoids.

• Authors: Giovanni Tulipano, John E Taylor, Heather A Halem, Rakesh Datta, Jesse Z Dong, Michael D Culler, Irene Bianchi, Daniela Cocchi, Andrea Giustina
• Journal: Pituitary (Pituitary) Vol. 10 Issue 3 Pg. 267-74 ( 2007) ISSN: 1386-341X [Print] United States
• PMID: 17587180 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• BIM-28125
• Blood Glucose
• Ghrelin
• Glucocorticoids
• Hormone Antagonists
• Phosphatidylinositols
• Receptors, Somatotropin
• Recombinant Proteins
• Insulin-Like Growth Factor I

Topics

• Adipose Tissue (drug effects, growth & development)
• Animals
• Blood Glucose (metabolism)
• CHO Cells
• Cricetinae
• Cricetulus
• Dose-Response Relationship, Drug
• Eating (drug effects)
• Epididymis (drug effects, growth & development)
• Ghrelin (analogs & derivatives, pharmacology)
• Glucocorticoids (antagonists & inhibitors, pharmacology)
• Growth (drug effects)
• Hormone Antagonists (pharmacology)
• Humans
• Insulin-Like Growth Factor I (metabolism)
• Male
• Obesity (chemically induced, pathology)
• Phosphatidylinositols (metabolism)
• Rats
• Rats, Sprague-Dawley
• Receptors, Somatotropin (drug effects)
• Recombinant Proteins (pharmacology)