We investigated licking and grooming (LG) levels received by each pup from their dams and the locomotor activity, anxiety-like behaviors, and stress reactivity in adult female offspring. We also investigated glucocorticoid receptor (GR) gene expression and its DNA methylation status in the hippocampus, comparing pups between and with-in litters. Rats that receive more LG than their siblings showed less anxiety-like behaviors and increased locomotor activity, regardless of their litter type. Higher licked pups also showed increased expression of the GR gene. Gene expression levels of the GR 17 splice variant were not significantly different as a function of dam LG or LG received, whereas DNA methylation levels at two CpG sites within GR17 promoter were significantly higher in high LG pups than low LG pups. Our results indicate that naturally occurring intra- and inter-litter differences in maternal LG have a lasting effect on the phenotypic outcomes of adult female offspring.

We investigated licking and grooming (LG) levels received by each pup from their dams and the locomotor activity, anxiety-like behaviors, and stress reactivity in adult female offspring. We also investigated glucocorticoid receptor (GR) gene expression and its DNA methylation status in the hippocampus, comparing pups between and with-in litters. Rats that receive more LG than their siblings showed less anxiety-like behaviors and increased locomotor activity, regardless of their litter type. Higher licked pups also showed increased expression of the GR gene. Gene expression levels of the GR 17 splice variant were not significantly different as a function of dam LG or LG received, whereas DNA methylation levels at two CpG sites within GR17 promoter were significantly higher in high LG pups than low LG pups. Our results indicate that naturally occurring intra- and inter-litter differences in maternal LG have a lasting effect on the phenotypic outcomes of adult female offspring.