Adaptation of corticosterone--but not beta-endorphin--secretion to repeated blood sampling in rats

• Published in: Laboratory animals (London) Vol. 33; no. 2; pp. 185 - 191
• Main Authors: Haemisch, A, Guerra, G, Furkert, J
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.04.1999
• Subjects: Animal Welfare; Animals; beta-Endorphin - blood; beta-Endorphin - secretion; blood plasma; blood sampling; Blood Specimen Collection - adverse effects; Blood Specimen Collection - veterinary; Chromatography, High Pressure Liquid - veterinary; corticosterone; Corticosterone - blood; Corticosterone - secretion; diurnal variation; endorphins; Feedback; hormone secretion; Male; Radioimmunoassay - veterinary; rats; Rats - physiology; Rats - psychology; stress response; Stress, Physiological - blood; Stress, Physiological - etiology; Stress, Physiological - veterinary; Time Factors; WELFARE; STRESS BETA-ENDORPHIN; BLOOD-SAMPLING; CORTICOSTERONE
• ISSN: 0023-6772; 1758-1117
• DOI: 10.1258/002367799780578309

Effects of short-term repeated blood sampling on the secretion of corticosterone (CORT) and beta-endorphin (beta-END) were evaluated in male Wistar rats. Blood was drawn from the tail vein of conscious rats four times within 2 h both at the peak and trough period of the diurnal corticosterone secretion cycle. All rats were well accustomed to the procedure. The main findings were: (1) At both sampling intervals, CORT increased significantly in response to the first sampling and declined to baseline values in successive sample. (2) beta-END also increased significantly in response to the first sampling but remained elevated in successive samples. (3) Intensities of initial CORT and beta-END responses correlated positively with each other and with the baseline beta-END values. Feedback inhibition of CORT secretion with sustained elevation of beta-END titres suggests a moderate stress intensity of the repeated blood sampling procedures. In general, due to lack of short-term feedback inhibition, beta-END seems to reflect the effects of repeated administration of moderate intense stressors more closely than CORT.