Lactation vs formula feeding: Insulin, glucose and fatty acid metabolism during the postpartum period
figureposted on 08.05.2020, 17:23 by Ada Admin, Maria A. Ramos-Roman, Majid M. Syed-Abdul, Beverley Adams-Huet, Brian M. Casey, Elizabeth J. Parks
Milk production may involve a transient development of insulin resistance in non-mammary tissues to support redistribution of maternal macronutrients to match the requirements of the lactating mammary gland. In the present study, adipose and liver metabolic responses were measured in the fasting state and during a 2-step (10 and 20 mU/m2/min) hyperinsulinemic-euglycemic clamp with stable isotopes, in 6-week postpartum women who were lactating (n=12) or formula-feeding (n=6) their infants and who were closely matched for baseline characteristics (e.g., parity, body composition, intrahepatic lipid). When controlling for the low insulin concentrations of both groups, the lactating women exhibited a fasting rate of endogenous glucose production (EGP) that was 2.6-fold greater, and a lipolysis rate that was 2.3-fold greater than the formula-feeding group. During the clamp, the groups exhibited similar suppression rates of EGP and lipolysis. In the lactating women only, higher prolactin concentrations were associated with greater suppression rates of lipolysis, lower intrahepatic lipid and plasma triacylglycerol concentrations. These data suggest that whole-body alterations in glucose transport may be organ specific and facilitate nutrient partitioning during lactation. Recapitulating a shift toward noninsulin-mediated glucose uptake could be an early postpartum strategy to enhance lactation success in women at risk for delayed onset of milk production.