Growth hormone response to growth hormone-releasing peptide-2 in growth hormone-deficient Little mice
Clinics
; 67(3): 265-272, 2012. graf, tab
Article
in En
| LILACS
| ID: lil-623102
Responsible library:
BR1.1
ABSTRACT
OBJECTIVE:
To investigate a possible direct, growth hormone-releasing, hormone-independent action of a growth hormone secretagogue, GHRP-2, in pituitary somatotroph cells in the presence of inactive growth hormonereleasing hormone receptors. MATERIALS ANDMETHODS:
The responses of serum growth hormone to acutely injected growth hormone-releasing P-2 in lit/litmice, which represent a model of GH deficiency arising frommutated growth hormone-releasing hormonereceptors, were compared to those observed in the heterozygous (lit/+) littermates and wild-type (+/+) C57BL/6J mice.RESULTS:
After the administration of 10 mcg of growth hormone-releasing P-2 to lit/lit mice, a growth hormone release of 9.3±1.5 ng/ml was observed compared with 1.04±1.15 ng/ml in controls (p<0.001). In comparison, an intermediate growth hormone release of 34.5±9.7 ng/ml and a higher growth hormone release of 163±46 ng/ml were induced in the lit/+ mice and wild-type mice, respectively. Thus, GHRP-2 stimulated growth hormone in the lit/lit mice, and the release of growth hormone in vivo may be only partially dependent on growth hormone-releasing hormone. Additionally, the plasma leptin and ghrelin levels were evaluated in the lit/lit mice under basal and stimulated conditions.CONCLUSIONS:
Here, we have demonstrated that lit/lit mice, which harbor a germline mutation in the Growth hormone-releasing hormone gene, maintain a limited but statistically significant growth hormone elevation after exogenous stimulation with GHRP-2. The present data probably reflect a direct, growth hormone-independent effect on Growth hormone S (ghrelin) stimulation in the remaining pituitary somatotrophs of little mice that is mediated by growth hormone S-R 1a.Key words
Full text:
1
Collection:
01-internacional
Database:
LILACS
Main subject:
Oligopeptides
/
Growth Hormone
/
Receptors, Pituitary Hormone-Regulating Hormone
/
Receptors, Neuropeptide
Limits:
Animals
Language:
En
Journal:
Clinics
Journal subject:
MEDICINA
Year:
2012
Document type:
Article
/
Project document
Affiliation country:
Brazil
/
United States