Search Results

You are looking at 1 - 1 of 1 items for

  • Author: I Ahnfelt-Ronne x
  • Refine by access: Content accessible to me x
Clear All Modify Search
J Svensson
Search for other papers by J Svensson in
Google Scholar
PubMed
Close
,
S Lall
Search for other papers by S Lall in
Google Scholar
PubMed
Close
,
SL Dickson
Search for other papers by SL Dickson in
Google Scholar
PubMed
Close
,
BA Bengtsson
Search for other papers by BA Bengtsson in
Google Scholar
PubMed
Close
,
J Romer
Search for other papers by J Romer in
Google Scholar
PubMed
Close
,
I Ahnfelt-Ronne
Search for other papers by I Ahnfelt-Ronne in
Google Scholar
PubMed
Close
,
C Ohlsson
Search for other papers by C Ohlsson in
Google Scholar
PubMed
Close
, and
JO Jansson
Search for other papers by JO Jansson in
Google Scholar
PubMed
Close

Growth hormone (GH) is of importance for normal bone remodelling. A recent clinical study demonstrated that MK-677, a member of a class of GH secretagogues (GHSs), increases serum concentrations of biochemical markers of bone formation and bone resorption. The aim of the present study was to investigate whether the GHSs, ipamorelin (IPA) and GH-releasing peptide-6 (GHRP-6), increase bone mineral content (BMC) in young adult female rats. Thirteen-week-old female Sprague-Dawley rats were given IPA (0.5 mg/kg per day; n=7), GHRP-6 (0.5 mg/kg per day; n=8), GH (3.5 mg/kg per day; n=7), or vehicle administered continuously s.c. via osmotic minipumps for 12 weeks. The animals were followed in vivo by dual X-ray absorptiometry (DXA) measurements every 4th week. After the animals were killed, femurs were analysed in vitro by mid-diaphyseal peripheral quantitative computed tomography (pQCT) scans. After this, excised femurs and vertebrae L6 were analysed by the use of Archimedes' principle and by determinations of ash weights. All treatments increased body weight and total tibial and vertebral BMC measured by DXA in vivo compared with vehicle-treated controls. However, total BMC corrected for the increase in body weight (total BMC:body weight ratio) was unaffected. Tibial area bone mineral density (BMD, BMC/area) was increased, but total and vertebral area BMDs were unchanged. The pQCT measurements in vitro revealed that the increase in the cortical BMC was due to an increased cross-sectional bone area, whereas the cortical volumetric BMD was unchanged. Femur and vertebra L6 volumes were increased but no effect was seen on the volumetric BMDs as measured by Archimedes' principle. Ash weight was increased by all treatments, but the mineral concentration was unchanged. We conclude that treatment of adult female rats with the GHSs ipamorelin and GHRP-6 increases BMC as measured by DXA in vivo. The results of in vitro measurements using pQCT and Archimedes' principle, in addition to ash weight determinations, show that the increases in cortical and total BMC were due to an increased growth of the bones with increased bone dimensions, whereas the volumetric BMD was unchanged.

Free access