Biovariability, reference change values (RCV), and index of individuality (IOI) have not been previously described for NT-proANP or GDF15. Also, the relation of changes of these markers to other clinical variables or biomarkers is unknown. In 41 patients with stable chronic systolic dysfunction, NT-proANP and GDF15 were measured alongside with clinical variables/markers comprising NT-proBNP, hsTnT, and hsCRP at four sampling intervals (2 weeks, 1-, 2-, 3-month intervals). At 2 weeks, 1-, 2-, and 3-month-follow-up, individual NT-proANP variations were 27.1, 22.5, 28.9, 15.6%, respectively, corresponding to RCVs of 53.2, 62.4, 80.2, and 43.2%, respectively. For GDF15, the respective individual variations were 6.8, 4.1, 5.5, 6.8%, corresponding to RCVs of 18.8, 11.5, 15.3 and 18.8%. Neither changes of NT-proANP or GDF15 correlated with changes in any of the clinical variables or biomarkers examined except for GDF15 with renal function. Baseline hormonal levels and clinical variables did not consistently influence the extent of change. The IOI was 0.19-0.35 according to interval for NT-proANP and 0.06-0.09 for GDF 15. In patients with CHF preselected for clinical stability changes of NT-proANP at intermediate follow-up do not correlate with changes in other variables; changes of GDF15 inversely correlate with renal function. The extent of change in both markers is not related to baseline hormonal levels or other baseline variables. RCVs are high for NT-proANP and low for GDF15, while inter-individual variation is high in GDF15 and intermediate in NT-proANP.

Summary Veal calves often develop insulin resistance, hyperglycaemia and glucosuria. We have studied effects of age and nutrition on blood metabolites and hormones, with major emphasis on glucose and insulin, in four groups of veal calves from 66–69 kg until slaughter at 175–196 kg. Calves were fed milk replacers which differed with respect to lactose, total sugar, protein and fat content. Mean intakes in groups 1, 2, 3 and 4 of lactose (1.24, 1.08, 0.95 and 0.66 kg/d), total sugar (1.27, 1.10, 1.01 and 96 kg/d), crude protein (0.40, 0.48, 0.65 and 0.49 kg/d) and crude fat (0.32, 0.31, 0.37 and 0.46 kg/d) were different. Average daily gains were 1.46–1.49 kg and feed/gain ratios were 1.49–1.61 kg/kg. Glucose and insulin concentrations were not associated with protein and fat intakes, but followed lactose and total sugar intakes, albeit differently at the start and end of the growth trial. Thus, insulin concentrations were higher (P < 0.05) at the end than at start of the growth trial in all 4 groups, whereas glucose concentrations increased (P < 0.05) with increasing age in only group 2. In conclusion, lactose and total sugar intakes affected the degree of hyperglycaemia and modified hyperinsulinemia at a given age, but the age‐dependent rise of insulin concentrations could not be explained by hyperglycaemia alone.