Figure 9

Effects of genetic alterations. Mean IOP ± SEM is shown. There is no difference in IOP between 3 to 4 month old males with either the 129P2/Ola (n = 18) or C57BL/6J (n = 20) Y chromosome (Y Chr). The 129 Y Chr had been backcrossed to strain C57BL/6J for 11 generations. Similarly, 6 to 9 month old males and females that are homozygous for normal (+) or mutant (n) alleles of Car2 have similar IOPs (n = 18 and 14, respectively). However, 4 months old males homozygous for the Lepr diabetes and obesity causing mutation (db) had significantly higher IOPs than their heterozygous age and sex matched littermates. The average body weight of the homozygotes and heterozygotes was 59 g (range 50 to 64 g) and 35 g (range 28 to 41 g) respectively. Blood sugar levels in db /db males of this age are almost always in the diabetic range whereas those of heterozygotes are not [[27]]. This was recently confirmed in cohorts of approximately 25 males of each genotype (mean ± SD; db/db 422 ± 110 mg/dl ; db/+ 147 ± 19 mg/dl; Anthony Nicholson, The Jackson Laboratory, personal communication)