Strain differences in kidney function of inbred rats: 1. Glomerular filtration rate and renal plasma flow

Bodyweight, kidney weight and glomerular filtration rate showed significant differences between strains--70% of the total variance was ascribed to the between-strain variance component--while the renal plasma flow showed only a slight strain difference due to a high within-strain variance component (63%). Heritability in the broad sense was 0.78 for bodyweight, 0.85 for kidney weight, 0.66 for glomerular filtration rate and 0.35 for renal plasma flow. There were significant genetic correlations between bodyweight and kidney weight (0.90), bodyweight and glomerular filtration rate (0.73), and between glomerular filtration rate and renal plasma flow (0.71), but not between kidney weight and kidney functions. Significant environmental correlations could be calculated only between bodyweight and all other variables, so that for comparison between strains it seems better to correct renal functions for bodyweight than for kidney weight, which would increase the variation of glomerular filtration rate.