Prior aerobic exercise mitigates the decrease in serum osteoglycin and lipocalin-2 following high-glucose mixed nutrient meal ingestion in young men

Osteoglycin (OGN) and lipocalin-2 (LCN2) are hormones that can be secreted by bone and have been linked to glucose homeostasis in rodents. However, the endocrine role of these hormones in humans is contradictory and unclear. We examined the effects of exercise and meal ingestion on circulating serum OGN and LCN2 levels in eight healthy males (age: 28 [25, 30] years [median ± IQR] and BMI: 24.3 [23.6, 25.5] kg/m2). In a randomized crossover design, participants ingested a high-glucose (1.1 g glucose/kg body weight) mixed-nutrient meal (45% carbohydrate, 20% protein, and 35% fat) on a rest-control day and 3 h and 24 h after aerobic cycling exercise (1 h at 70-75% VO2peak). Acute aerobic exercise increased serum LCN2 levels immediately after exercise (~61%), which remained elevated 3 h post-exercise (~55%). In contrast, serum OGN remained similar to baseline levels throughout the 3 h post-exercise recovery period. The ingestion of a high-glucose mixed-nutrient meal led to a decrease in serum OGN at 90 min (~-17%) and 120 min postprandial (~-44%), and a decrease in LCN2 at 120 min postprandial (~-26%). Compared to the control meal, prior exercise elevated serum OGN and LCN2 levels at 120 min postprandial when the meal was ingested 3 h (OGN: ~74% and LCN2: ~68%) and 24 h post-exercise (OGN: ~56% and LCN2: ~16%). Acute exercise increases serum LCN2 and attenuates the postprandial decrease in OGN and LCN2 following high-glucose mixed-nutrient meal ingestion. The potential endocrine role of circulating OGN and LCN2 in humans warrants further investigation.