Variation in plasma concentration of insulin-like growth factor-1 and its covariation with liveweight in mice.
Three experiments were undertaken to examine the degree and causes of variation in plasma concentrations of insulin-like growth factor-1 (IGF-1) in mice. The relationship between IGF-1 concentrations and liveweight was also examined. In all three experiments, a number of non-genetic factors were found to contribute significantly to the variation in IGF-1 concentrations, the most important of these being sex and litter size. In one experiment, where pups from 16 litters were cross-fostered to avoid the confounding of maternal and direct genetic effects, a heritability of 0.40 +/- 0.27 was estimated for plasma IGF-1 concentration at 35 days of age. To examine further the existence of genetic variation in plasma concentrations of IGF-1 and the genetic covariation between plasma IGF-1 levels and other body traits, a selection experiment with mice has been initiated. Moderate to strong phenotypic correlations between IGF-1 concentrations and weight at an early age have been found in all three experiments.
Blair
H T
HT
Department of Animal Science, Massey University, Palmerston North, New Zealand.
McCutcheon
S N
SN
Mackenzie
D D
DD
Gluckman
P D
PD
Ormsby
J E
JE
D000375:Aging / Q000097:blood; D000818:Animals; D001835:Body Weight; D007334:Insulin-Like Growth Factor I / Q000097:blood* / Q000235:genetics; D051379:Mice; D008815:Mice, Inbred Strains; D010641:Phenotype; D012727:Sex Characteristics; D013002:Somatomedins / Q000097:blood*
D013002:Somatomedins; D007334:Insulin-Like Growth Factor I