Metabolism of exogeneous cortisol in tumor-bearing rats

The influence of cancer on endocrine, immune, and behavioral stress responses

“…Similar to a few studies in rodent models (Marc et al, 1974;Pyter et al, 2009), results from dexamethasone suppression tests in cancer patients indicate that HPA axis negative feedback checkpoints are altered in cancer patients, not just glucocorticoid secretion. This is demonstrated by faster decline of cortisol post-stressor in women with breast cancer (van der Pompe et al, 1996).…”

“…Several conflicting reports exist in which corticosterone is reduced in tumor-bearing models or similar to tumor-free controls at baseline (Bernstein et al, 1985;Bojkova et al, 2011;Mocchegiani et al, 1999;Pyter et al, 2009;Warren et al, 1987;Zepp and Gray, 1983). Also, less corticosterone is bound to plasma carrier proteins in tumor-bearing rats, making it prone to metabolism and poor transport, and therefore, less biologically active (Marc et al, 1974). This may mediate, in part, the observations that tumor-bearing models display elevated baseline corticosterone concentrations, if these studies primarily measure unbound or "free" corticosterone.…”

“…Increases in these receptors may signify a more rapid and efficient glucocorticoid negative feedback regulation, thereby explaining reduced post-stressor corticosterone responses. Furthermore, metabolism of exogenously administered cortisol is increased in tumor-bearing mice (Marc et al, 1974). If cortisol metabolism is parallel to endogenous corticosterone metabolism, this work suggests that corticosterone may have a shorter window of bioactivity in tumor-bearing rodents.…”

“…If cortisol metabolism is parallel to endogenous corticosterone metabolism, this work suggests that corticosterone may have a shorter window of bioactivity in tumor-bearing rodents. Part (Marc et al, 1974). However, two studies suggest that the subsequent corticosterone recovery from peak back to baseline values after a stressor may be delayed in tumor-bearing rodents (Pyter et al, 2009;Vegas et al, 2006).…”