Phenotypes Associated with This Genotype

Genotype
MGI:3041405

• Allelic Composition: Ghsr^tm1Rgs/Ghsr^tm1Rgs
• Genetic Background: involves: 129 * C57BL/6J

• ♀: phenotype observed in females
• ♂: phenotype observed in males
• N: normal phenotype

growth/size/body

decreased body weight ( J:89243 )

• from 16 to 24 weeks of age homozygotes exhibit a modest reduction in body weight relative to wild-type control mice

• however, no significant difference in cumulative or biweekly food intake is observed in 16- to 24-week-old homozygotes relative to wild-type mice

homeostasis/metabolism

homeostasis/metabolism phenotype ( J:89243 , J:151960 )

N • despite a modestly lower body weight, homozygotes exhibit no significant differences in fat and muscle content relative to wild-type mice, as determined by NMR spectroscopy (J:89243)

N • in the fasted state, homozygotes show a normal increase in serum ghrelin levels along with a similar decline in serum leptin and insulin levels relative to wild-type mice (J:89243)

N • in addition, fed and 24- and 48-hr fasted homozygotes show no differences in core body temperature relative to wild-type mice, suggesting a normal metabolic rate (J:89243)

N • mice subjected to cold and fasting exhibit normal thermoregulation and sleep amounts (J:151960)

decreased circulating insulin-like growth factor I level ( J:89243 )

• at 24 weeks of age, both male and female homozygotes display reduced serum IGF-1 levels relative to wild-type mice

abnormal growth hormone level ( J:89243 )

• unlike the response in wild-type mice, acute administration of ghrelin or MK-0677 fails to stimulate GH release in homozygous mutant mice

• in contrast, hGHRH administration stimulates GH release in both wild-type and homozygous mutant mice

abnormal response/metabolism to endogenous compounds ( J:89243 )

• unlike the response in wild-type mice, administration of ghrelin fails to stimulate either GH release or food intake in homozygous mutant mice

behavior/neurological

abnormal food intake ( J:89243 )

• unlike the response in wild-type mice, administration of ghrelin (10 g per mouse) fails to induce food intake in homozygous mutant mice

• however, no significant changes in body weight and food intake are observed when homozygotes are fasted for 24 hrs and subsequently refed, or in short period (0.5 hrs, 1.0 hrs, and 2.0 hrs) food consumption after either 24 hrs or 48 hrs of fasting

skeleton

skeleton phenotype ( J:89243 )

N • at 24 weeks of age, homozygotes display normal bone growth, with no significant differences in bone mineral density or content relative to wild-type mice