This study evaluates the effect of insulin in the association between nutrition and gender during lactation on inducing changes in heart morphology of pups when adults. Two groups of lactating rat dams were fed a normal diet containing 22% protein or 0% protein during the first 10 days of lactation. Eight-day-old rats from the female control group (FC) displayed a heart weight/body weight (H/B) ratio 100% greater when compared with the male control group (MC). An increased H/B ratio (65%) was found in the MC group when compared with the male malnourished group (MM). An effect on the development was present in the FC group in which, at 8 days, the H/B ratio was 70% greater than in this group at 60 days of age. A similar effect was observed in the female malnourished group (FM), where the H/B ratio was 100% greater. The effect on the development, at 8 days, in the FC group, when compared with the females at 60 days, displayed a larger cardiomyocyte volume [QA(c)] and a higher cardiomyocyte density [Vv(c)]: QA[c] 220% greater (p < 0.05) and Vv[c] 530% greater (p < 0.01). The FM group, at 8 days of age, had the QA[c] and Vv[c] greater than at the age of 60 days: QA[c] 100% greater (p < 0.05) and Vv[c] 290% greater (p < 0.05). The insulin/glucose ratio reflected the variable gender associated with the malnourishment in the male animals at 8 days of age. In these animals the insulin/glucose ratio of the malnourished animals was found to be reduced by 42% when compared with the control groups. At 60 days of age, a difference in the insulin/glucose ratio was present between FC and FM groups (33% greater in the FC group, p < 0.05). Gender was associated with a high insulin/glucose ratio in MC and MM groups when compared with the FC and FM groups. Also this association was observed in the animals at 60 days of age when the insulin/glucose ratio of the MM animals was 45% greater than that observed in the FM group.
Copyright 2004 S. Karger AG, Basel