EFFECTS OF ADRENALINE INFUSION ON THE INTERSTITIAL ENVIRONMENT OF SUBCUTANEOUS ADIPOSE-TISSUE AS STUDIED BY MICRODIALYSIS

1. Adrenaline was infused at a rate of 25 ng min(-1) kg(-1) into seven healthy volunteers and its effects on adipose tissue were studied by microdialysis. 2. Adrenaline infusion led to a rapid rise in plasma ad renaline concentration from a basal value of 0.15 +/- 0.03 nmol/l to a peak value of 1.82 +/- 0.15 nmol/l within 30 min (analysis of varianc e: P< 0.001), Plasma noradrenaline levels increased from the basal val ue of 1.48 +/- 0.21 nmol/l to 1.78 +/- 0.20 nmol/l within 30 min of in fusion (analysis of variance: P < 0.05). Once the infusion was stopped the plasma adrenaline and noradrenaline levels returned to basal valu es within 15 min. 3. The arterialized blood glycerol concentration inc reased from the basal value of 47 +/- 6 mu mol/l to 101 +/- 8 mu mol/l (analysis of variance: P < 0.001), and the interstitial glycerol conc entration increased from 181 +/- 17 mu mol/l to 350 +/- 47 mu mol/l (a nalysis of variance: P < 0.001) within 30 min of adrenaline infusion. Thereafter the concentrations declined gradually towards basal values, When the infusion was discontinued the levels declined further, below the basal value. 4. Adrenaline infusion caused a significant increase in the plasma glucose and blood lactate concentration (analysis of va riance: P<0.001 and P< 0.001), but no such effect was observed in the interstitial concentrations. 5. The basal dialysate concentrations of adrenaline and noradrenaline were 43 +/- 37 pmol/l and 1170 +/- 430 pm ol/l respectively. There were difficulties in estimating the absolute interstitial concentrations of adrenaline and noradrenaline which are discussed. The dialysate adrenaline concentration increased to a peak value of 112 +/- 48 pmol/l (analysis of variance: P < 0.05) within 30 min. The dialysate noradrenaline concentration increased to a peak val ue of 2830 +/- 1470 pmol/l, but the rise was not significant. 6. These results show that the interstitial concentrations of metabolites and hormones can be significantly different from those of blood and plasma and these differences reflect tissue specialization.