Substrate diffusion through cell membranes also accounted for the observed time-dependency of bioluminescent reaction rates, which by virtue of the induced spatial heterogeneities resembled fractallike reaction kinetics. The afore-mentioned model fits the experimental data points with good accuracy, thereby enabling reliable quantitative insights into the bioluminescence reaction kinetics for both cell lysates and intact cells. Microscale measurements of oxygen concentration were performed by integration of fluorescent oxygen sensitive microbeads that we previously developed. Stable read-outs of oxygen concentration over a time period of 3 days were obtained for control gels in which no cells were embedded. Radial oxygen concentration profiles from cell-seeded hydrogels displayed a gradual decrease towards the center with an averaged availability of oxygen that increased over time. Dynamic time point measurements of the average photon flux emitted from the cell-seeded hydrogels revealed the presence of a fast bioluminescence intensity peak that fades away slowly with a decaying signal that was detectable for several hours. Peak intensities reached maximum values after 2 days of cultivation and decreased gently with longer cultivation time. These results did however not entirely correlate to the quantitative DNA and viability measurements, representing the active bioluminescent cell population and clearly being oxygenindependent readouts. To decouple bioluminescence signal reshaping caused by oxygen availability from the spatial distribution of luciferase activity, we removed cell respiration in our model, hence maintaining a saturated oxygen level within the hydrogel and therefore oxygen-independent bioluminescence signal intensities. A prominent role for oxygen in reshaping the bioluminescence signal was clearly observed. When saturated oxygen conditions were simulated the obtained peak signal intensities matched closely the cell activity measurements. Radial profiles of the bioluminescence signal emitted from encapsulated 293T cells indicated high activity near the hydrogel edge at early time points that gradually leveled off towards the center after longer measurement times. With increasing cultivation times the observed effect of high edge activity became more pronounced and was in good agreement with our simulation results. Combined, these data show a strong influence of oxygen availability on the activity of luciferase reporter cells which should be taken into account when intrinsic measurements and error-free interpretations of bioluminescence intensity are pursued. Obesity, a state of excessive adipose tissue, has long been known to be a risk factor for the development of cardiovascular disease. Adipose tissue has been traditionally considered a fat-storage organ, but is now known to have an active role in systemic metabolism through the active secretion of adipokines.