Cortisol and prolactin concentrations during repeated blood sample collection from freely moving, mouse-sized mammals (Phodopus spp.) (original) (raw)
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Hormones and Behavior, 2006
An outbred species of dwarf hamster (Phodopus campbelli) was used to assess between-individual variability in the response to, and recovery from, a one-time stressor of 6 min of physical restraint in a subordinate, on-back, position. Four repeated plasma samples were drawn under homecage isoflurane anesthesia from 33 males and 38 females 50 min before, and then 10, 60, and 120 min after the stress onset. Plasma cortisol concentrations were higher in females than males, but there was no evidence for a sex difference in response to the stressor. The expected crosssectional increase (∼50 ng/ml) in response to the stressor, followed by recovery, was seen. However, there was extensive individual variation, ranging from no reaction to continuous decline from the initial to the final sample. Results were expressed in four ways (absolute concentration, relative concentration, and area under the curve relative to ground and relative to the stress-induced increase) and also standardized and subjected to hierarchical cluster analysis. Clusters failed to effectively partition the between-individual variation and did not cluster by sex, age, or housing conditions. The current study cautions against ignoring individual differences and suggests that outbred animal models might be particularly relevant to understanding stress-related pathological conditions.
Stressors, Including Social Conflict, Decrease Plasma Prolactin in Male Golden Hamsters
Hormones and Behavior, 1995
Following exposure to a stressor, plasma prolactin (PRL) rises in most species. The purpose of the present study was to examine the effect of social conflict or of footshock stress on PRL responsiveness in male Syrian hamsters. Contrary to expectations, PRL was significantly lower in subordinate hamsters than in their dominant opponents or in controls following one, five, or nine exposures to social conflict. Similarly, PRL was reduced in hamsters subjected to a mild footshock stressor. By contrast, adrenocorticotropin, another stress-responsive hormone, was elevated following exposure to each of these stressors. We also demonstrate that PRL release is inhibited by dopamine as it is in other species by showing that there is a dose-dependent increase in PRL release following treatment with the dopamine receptor blocker, domperidone. ᭧ 1995 Academic Press, Inc. 1 The views of the author(s) do not purport to reflect the position of the Department of the Army or the Department of Defense (para. 4-3, AR 360-5). 2 Research was conducted in compliance with the Animal Welfare Act and other Federal statutes and regulations relating to animals and experiments involving animals and adheres to principles stated in the Guide for the Care and Use of Laboratory Animals, NIH publication 85-23.
Animal Welfare, 2012
Minimising the effects of restraint and human interaction on the endocrine physiology of animals is essential for collection of accurate physiological measurements. Our objective was to compare stress-induced cortisol (CORT) and noradrenalin (NorA) responses in automated vs manual blood sampling in pigs. A total of 16 pigs (30 kg) were assigned to either: (i) automated blood sampling via an indwelling catheter using a novel-penning system called PigTurn® which detects the pig's rotational movement and responds by counter-rotating, allowing free movement while preventing catheter twisting; (ii) automated sampling while exposed to visual and auditory responses of manually sampled pigs; or (iii) manual sampling by jugular venipuncture while pigs were restrained in dorsal recumbency. During sampling of (i), personnel were not permitted in the room; samplings of (ii) and (iii) were performed simultaneously in the same room. Blood samples were collected every 20 min for 120 min and measured for CORT (ng ml -1 ) using mass spectrometry and NorA (pg ml -1 ) using High Performance Liquid Chromatography (HPLC). Effects of treatment and time were computed with mixed models adjusted by Tukey post hoc CORT and NorA concentrations were lowest in group (i) followed by group (ii), which were not different. However, CORT and NorA levels in manually sampled animals (iii) were highest compared to automated methods (i) and (ii). Plasma concentrations across time were not different for CORT, but NorA concentration at time 0 min was higher than at 120 min. The presence of visual and auditory stimuli evoked by manual sampled animals did not affect non-handled pigs' responses. Restraint and manual sampling of pigs can be extremely stressful while the automated blood sampling of freely moving pigs, housed in the PigTurn® was significantly less stressful for the animals.
General and Comparative Endocrinology, 2012
Wildlife capture methods can make it impractical or impossible to obtain baseline plasma glucocorticoid (GC) levels, and the time of capture of individual animals is often unknown so there may be little uniformity in the duration of capture-stress prior to blood collection. Although baseline samples are preferred, if seasonal changes in capture-stress GC levels closely reflect seasonal baseline changes, then capturestress GC levels can be used to infer at least the direction of change in baseline levels; and if GC levels are relatively constant during long periods of capture, then lack of consistent capture durations are not problematic. These are empirical questions that need to be assessed for each species, and here we present our data for male Richardson's ground squirrels (Urocitellus richardsonii) sampled in prebreeding and postbreeding periods. We compared cortisol levels in blood samples taken within 3 min of capture (BASE), after 30 min of capture-stress (STRESS-1), and after >1.5 h of capture-stress (STRESS-2). We found that STRESS-2 cortisol levels did not change in unison with BASE levels, nor were STRESS-2 levels always equal to STRESS-1 levels. The importance of obtaining a baseline sample was further highlighted by our finding that prebreeding BASE cortisol levels were elevated to capture-stress-induced levels, leaving the animals almost no ability to respond to the stress of capture. In contrast, BASE cortisol levels in postbreeding animals were low and most animals responded robustly to capture. Those postbreeding animals that did not respond had high corticosteroid binding globulin levels that buffered the animals against the increase in total cortisol. STRESS-2 cortisol levels were useful for revealing how animals respond to sustained capture-stress, and revealed the same substantial variation among individuals observed in STRESS-1 blood samples, but they missed dramatic changes in baseline levels that are important for understanding the full context of seasonal changes in the functioning of the HPA axis.
Comparative Biochemistry and Physiology - A Physiology, 1997
Glucocorticoids, secreted in response to perceived stress, can suppress immunoglobulin (Ig) levels and compromise immune function in mice and rats. Prairie voles (Microtus ochrogaster) have been reported to exhibit basal corticosterone concentrations that would cause pathological changes in the immune function of most other rodents. The goals of the present study were to verify that serum corticosterone concentrations are high in prairie voles, as compared with house mice (Mus musculw), by measuring serum corticosterone with the same RIA; to examine the effects of mild stressors on corticosterone response in both species and to examine the effects of elevated corticosterone levels on IgM and IgG levels in prairie voles and house mice. After 2
Many studies on stress and pain rely, solely or mainly, on plasma cortisol assessment. Confounding factors, such as handling, may cause a release of cortisol making the interpretation of the results difficult. We looked at the influence of duration of restraint on the plasma cortisol levels of one-to-two month old calves. Forty-three calves were divided into four groups according to the interval between restraint and blood sampling: i) Group 0, immediate blood-sampling; ii) Group 0.5M, half a minute restraint; iii) Group 1M, one minute restraint and iv) Group 2M, two minutes restraint. The only increase in plasma cortisol, compared with all the other groups, was seen with blood sampling after two minutes of restraint. This study provides evidence to suggest that cortisol released as a result of handling stress is not evident if blood sampling is carried out within one minute of restraining calves.
Physiology & Behavior, 1993
RUSHEN, J., N. SCHWARZE, J. LADEWIG AND G. FOXCROFT. Opioid modulation of the effects of repeated stress on ACTH, cortisol, prolactin, and growth hormone in pigs. PHYSIOL BEHAV 53(5) 923-928, 1993.--Prepubertal gilts (n = 16) were restrained with a nose snare for 15 rain each day over 9 days. At the beginning of the first and last nose snare, the animals were also injected IV with 1 mg/kg of naloxone. Blood samples were taken before and after restraint at 15-min intervals and plasma assayed for ACTH, cortisol, prolactin, and GH. The initial restraint led to significant increases in ACTH, cortisol, prolactin, and GH concentrations. There was no evidence of a reduction in the magnitude of endocrine responses with repeated restraint. Indeed, the response of GH was more apparent after the final restraint. In the absence of the restraint, naloxone elevated cortisol and ACTH concentrations. Naloxone, given with the first restraint, enhanced the increase in ACTH, cortisol, and prolactin. Naloxone, given during the last restraint, inhibited the increase in GH, but had less effect upon cortisol and prolactin concentrations than during the initial restraint. Gilts genetically selected for a high cortisol response to ACTH injections had a higher basal cortisol concentration and a higher cortisol response to restraint than gilts selected for a low cortisol response to ACTH. However, there were no differences between these groups in ACTH, prolactin, or GH concentrations, or in any endocrine response to naloxone. Endogenous opioids can inhibit pituitary-adrenocortical responses and enhance GH responses of pigs to stress. Measures of cortisol concentrations are poor predictors of prolactin and GH responses to stress.