title: Adaptation of corticosterone-but not beta-endorphin-secretion to repeated blood sampling in rats.
abstract: 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 samples. (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.
authors.affiliation: Abteilung für Klinische Neurobiologie, FU Berlin.
authors.forename: A
authors.initials: A
authors.lastname: Haemisch
authors.forename: G
authors.initials: G
authors.lastname: Guerra
authors.forename: J
authors.initials: J
authors.lastname: Furkert
mesh_terms: D000827:Animal Welfare; D000818:Animals; D001800:Blood Specimen Collection / Q000009:adverse effects / Q000662:veterinary*; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D003345:Corticosterone / Q000097:blood / Q000378:metabolism*; D005246:Feedback; D008297:Male; D011863:Radioimmunoassay / Q000662:veterinary; D051381:Rats / Q000502:physiology / Q000523:psychology*; D013312:Stress, Physiological / Q000097:blood / Q000209:etiology / Q000662:veterinary*; D013997:Time Factors; D001615:beta-Endorphin / Q000097:blood / Q000378:metabolism*
chemical_list: D001615:beta-Endorphin; D003345:Corticosterone