Pups within each drug pretreatment group were separated from their dams 24 hr after injection. Pups were randomized into baseline control, 90 min normoxia time control, and 90 min hypoxia (8% O2). An inspired O2 of 8% gives a SpO2 of 80%–85% which is clinically relevant in the NICU (Borenstein‐Levin et al., 2020; Bruder, Taylor, et al., 2008; Cumpstey et al., 2020). The 90‐min normoxic samples are the control for hypoxia and serve to evaluate the effects of fasting on glucose and insulin without and with concomitant hypoxia. For the purposes of this report, we use “separation” and “fasting” synonymously depending on the context. Trunk blood samples were obtained by decapitation and collected in tubes containing K2EDTA. In postnatal day 2 (PD2) pups, 2–3 samples were pooled and considered n = 1 for statistical analyses (Bruder et al., 2011). PD7, PD14, and PD21 samples consisted of one pup per K2EDTA tube.