Effect of age on serum chemistry profile, electrophoresis and thyroid hormones in beagle dogs two weeks to one year of age.

Chemistry tests were conducted on serum from young Beagle dogs in order to deter mine the effect of age on these parameters. Blood was collected at regular intervals from 25 normal Beagle puppies (13 males and 12 females) at ages ranging from 2 weeks to 12 months. Serum chemistry profiles, protein electrophoresis and radioimmunoassays for thyroxine and triiodothyronine were included. Rapidly changing age related differences were observed in several parameters. Urea nitrogen, cholesterol, triglycerides, lactate dehydrogenase, thyroxine, glucose, gamma glutamyl transpeptidase, and total bilirubin values were elevated early in life, and decreased during the first 6 to 8 weeks, while alanine aminotransferase activity was low initially and increased during this period. Lactate dehydrogenase, thyroxine, gamma glutamyl transpeptidase, total bilirubin and alanine aminotransferase attained stability by 3 months, but the remaining parameters showed slight changes subsequently, gradually approaching adult values. More gradual age related changes were observed in other parameters. These included alkaline phosphatase, inorganic phosphorus and calcium values, which were higher in younger dogs, and creatinine, aspartate aminotransferase and total protein values, which were lower in younger dogs. Creatinine and aspartate aminotransferase values were stable by approximately 6 months; alkaline phosphatase, inorganic phosphorus, calcium and total protein values continued to change gradually up to 1 year.

Age-related changes in serum chemistry and hematology values in normal Sprague-Dawley rats.

Age-related changes in serum chemistry and hematology values in male and female Sprague-Dawley rats 2 to 29 months of age are described. The number of values per determination (N) ranged from 554 to 1126. Serum chemistry parameters demonstrating changes with time included inorganic phosphorus, total protein, cholesterol, triglycerides, and alkaline phosphatase. There was little or no sex difference among these parameters. Hematologic parameters demonstrating changes with time included leukocyte elements (lymphocytes, neutrophils, eosinophils, monocytes), erythrocyte parameters (red blood cell count, hematocrit, hemoglobin, mean cell volume, mean cell hemoglobin), and platelet count. Most trends in erythrocyte parameters were more marked in males than in females. To visualize the effect of age of these parameters, the data were plotted vs time, and fitted models were superimposed on the graphs. Comparisons with available literature values are made, and the value of an age-related data base when conducting long-term toxicity studies is discussed.

Reference range data base for serum chemistry and hematology values in laboratory animals.

A reference range data base containing serum chemistry and hematology values on over 3000 animals is described. Data listed include the mean, standard deviation, and 10th and 90th percentiles for each of the following parameters. Serum chemistry: sodium, potassium, chloride, calcium, inorganic phosphorus, urea nitrogen, creatinine, total bilirubin, total protein, glucose, cholesterol, triglycerides, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltransferase (monkey only), lactate dehydrogenase (dog only), and creatine kinase (dog only). Hematology: hematocrit, hemoglobin, red blood cells, reticulocytes, mean cell volume, mean cell hemoglobin, mean cell hemoglobin percent, platelets, white blood cells, neutrophils, eosinophils, basophils, lymphocytes, monocytes, and stabs. The species included are mouse, rat, hamster, rabbit, beagle dog, and cynomolgus monkey. The use of the reference ranges in routine computerized data collection is discussed.