Figure 1. Schematic of experimental protocol and time line for the study.

Exposure to either intermittent hypoxia (IH) or intermittent air (IA) occurred during the 12 h of the light (L) period (all animals kept in constant room air during dark (D) period) with a simultaneous infusion of either 0.9% sodium chloride (saline infusion) or 50% dextrose (glucose infusion) containing 500 μg ml⁻¹ bromodeoxyuridine (BrdU) at a constant rate of 100 μl h⁻¹. *Arterial blood was sampled twice daily: immediately prior to lights on at 8 am and 10 h into the light period at 6 pm. For each blood sample a total of 100 μl whole blood was removed and 2 μl used to measure blood glucose, insulin and corticosterone. Plasma was extracted from the remaining blood and the red blood cells re-suspended and re-infused into the mouse.