Reproduction Abstracts

Introduction: Maternal depletion of insulin in serum and branched-chain amino acids (BCAA) in uterine luminal fluid occurs in response to dietary protein undernutrition during the periconceptional period which leads to adverse offspring growth and cardiovascular phenotype (e.g. high blood pressure). This study aimed to determine whether insulin and/or BCAA depletion might be inductive in vivo factors for postnatal phenotype using an in vitro embryo culture model.

Materials and methods: Two-cell embryos were cultured to the blastocyst stage in KSOM medium supplemented with insulin and BCAA at normal (N, 100%) or low (L, 50%) concentrations: N-Insulin+N-bcaa, L-Insulin+N-bcaa, N-Insulin+L-bcaa, and L-Insulin+L-bcaa. Control medium (N-Insulin+N-bcaa) was supplemented with serum insulin (1 ng/ml) and uterine luminal fluid concentrations of 19 amino acids, including BCAA (valine (0.46 mM), isoleucine (0.21 mM), leucine (0.32 mM)), found in well-fed mice. Blastocysts were transferred to pseudopregnant recipients.

Results and discussion: Males and females from the L-Insulin+L-bcaa group showed an increased birth weight and higher body weight at weeks 5–7 and 4–6 in males and females respectively compared to the control group. Mean blood pressure (taken at weeks 9, 15 and 21) was not affected in females. However, males from the L-Insulin+L-bcaa group showed a higher mean blood pressure than controls at week 9. Our data show that the combined depletion of insulin and BCAA during early embryo development can induce increased growth and high blood pressure in offspring during early postnatal development, independent of litter size, mimicking in broad terms effects caused by maternal dietary protein restriction. Funded by BBSRC BB/1001840/1.