Objective To study the effects of living environment conditions and animal-animal interaction on the blood hormone levels and psychological behavior in Chinese tree shrews .Methods Chinese tree shrews were raised in ca-ges of different space sizes or were administered reserpine for 15, 30, 60, 120, 180 days, respectively.Then the animals were anesthetized by ether inhalation , and blood samples were taken from the heart to detect the levels of blood testosterone (T), estradiol (E2), endothelin (ET), adrenaline (A) and noradrenaline (NA) by radioimmunoassay (RIA).Results 1.Chinese tree shrews were bred in large cage (D1group) or small cage (X1 group) for 15, 30, 60, 120, 180 days, re-spectively.Compared with the animals bred in the large cage (D1 group), the level of blood testosterone (T) was signifi-cantly reduced (P<0.01), and the levels of adrenaline , noradrenaline and endothelin were significantly increased in the small cage group (P<0.01 for all).2.The animals raised in small cages in close neighborhood with large cages for 15, 30, 60, 120, 180 days, respectively.The levels of testosterone, adrenaline and noradrenaline in the large cage group (X2 group) were significantly higher than those of the small cage group (X1 group) (P<0.01 for all).3.The adrenaline and noradrenaline levels were significantly lower in all the reserpine groups (P<0.01 for all).4.The animals bred in small cages (X1 group) and in small cages in close neighborhood with large cages showed sudden loss , reduced appetite, testicu-lar atrophy , penile prolapse and stress symptoms .The animals of the reserpine groups appeared gentle temperament , signif-icantly reduced activity and reduced appetite .However , after stopping the reserpine administration and feeding them in large cages , the animals gradually returned to normal behavior .Conclusion Both animals living environment conditions and animal-animal interaction may cause changes of blood hormone levels and psychological behavior in Chinese tree shrews.

【Objective】 To develop and verify a kinetic method for the determination of prekallikrein activator (PKA) content. 【Methods】 The optimal reaction conditions were determined by comparing the factors of pH and ionic strength of different sample dilution buffers, incubation time of each procedure, and incubation temperature. The accuracy, specificity, precision, linearity, stability and durability of the method were validated. 【Results】 The sample was diluted with 0.05 mol/L Tris-HCl buffer (pH8.5, containing 0.15 mol/L NaCl) and incubated by prekallikrein (PK) at 37℃ for 20 min. After that, the substrate S-2302 was added. Within 10 min before the measurement, the absorbance change rate reached △A405/min. The validation results indicated that the linear range of the method was (0.5~4.0)IU/mL, while the recovery of calibration standard was 96.9%~103.7% with the R² value more than 0.99. The specificity test showed that human serum albumin, excipients of intravenous human immunoglobulin (pH4), low pH and protein content had no significant effect on the detection of PKA, The recovery rates of standard sample solution in the specificity experiment were 98.0% (0.9% sodium chloride solution), 95.3% (0.46% sodium caprylate solution), 96.7% (10% maltose solution, pH4.0), 94.0%(20%BSA), and 94.0%(5%BSA, pH4.0), respectively. The accuracy and precision of the method can meet requirements in the range between 0.5 and 4.0 IU/mL. The inter-batch recovery rate of quality control samples were between 96.4%~109.5% with the coefficients of variation(CV) between 0.2%~6.9%, while the intra-batch recovery rate were between 101.5%~102.9% with the CV between 2.6%~5.9%. The linearity, accuracy and precision of the assay can meet the requirements when PK and S-2302 were placed at room temperature for less than 6 hours, with the recovery rate of quality control samples between 94.9%~109.9%. The end-point method and kinetic method were used to determine the PKA in 20 batches of human serum albumin, and the consistency showed that there was no significant difference between the two methods(P>0.05). 【Conclusion】 A kinetic method for determination of PKA content with good linearity, specificity, accuracy, precision, stability and durability has been established. Compared with the method in ChP, the new method is more convenient, accurate and rapid to determine the content of PKA in human albumin and human immunoglobulin (pH4) for intravenous injection.