HIGHER CORTICOSTERONE VALUES AT A FIXED SINGLE TIMEPOINT IN SERUM FROM MICE TRAINED BY PRIOR HANDLING

  • 1 January 1978
    • journal article
    • research article
    • Vol. 5  (1) , 1-13
Abstract
Results of training rodents for bioassay of synthetic corticosteroids were not consistent with expectations based upon earlier implied claims stemming, perhaps, from overt behavioral patterns displayed by handled as compared to nonhandled rodents. At the timepoints investigated, habituation of mature mice and rats by exposure to handling, injection and killing procedures resulted in statistically significantly increased corticosterone concentrations. For younger animals the elevation in corticosterone concentration might also have been applicable. Lowest hormone concentration occurred in the groups of mice housed undisturbed in an animal chamber separate from the room housing mice subjected to habituation. For certain rodents kept in L [light] from 0600-1800 habituation for 1 wk at least at the circadian stage corresponding to 0800, was not only ineffectual (in eliminating the rise in serum corticosterone associated with handling) but detrimental to the evaluation of synthetic corticosteroid potency by bioassay (to the extent that such a rise was exaggerated rather than reduced). In these acute experiments, methylprednisolone was more suppressive than dexamethasone and the water soluble ester-salts less suppressive than the 21-hydroxy bases. Important differences may be present in the distributive stage and/or the metabolism of these compound-factors affecting the speed of onset of the desired as well as undesired effects.