Session: SUN 72-87-HPA Axis
Poster Board SUN-83
We maintained adult Long Evans male rats on either a low-fat chow (10% fat) or a palatable high-fat diet (HFD) (41% butter fat) prior to surgery. Animals received either sham surgery (SHAM), vertical sleeve gastrectomy (VSG) or roux-en-Y gastric bypass (RYGB). Both VSG and RYGB lost approximately 15% of their body weight following the surgeries. Four weeks after surgery, anxiety- and depressive-like behaviors were assessed in all 4 groups. Both obese SHAM rats and surgically-induced lean rats (VSG and RYGB) had a minimal phenotype with respect to either anxiety-like (elevated plus maze) or depressive-like (modified forced swim test) stress behaviors. However, RYGB increased basal tone of the HPA axis as measured by a.m. and p.m. corticosterone. RYGB also produced thymic involution and adrenal hyperplasia, consistent with the idea of increased basal HPA drive. Moreover, during an acute novel environment test, RYGB exhibited reduced plasma ACTH and corticosterone responses to the stress, suggestive of reduced post-stress HPA responsivity, possibly due to increased negative feedback from the elevated basal glucocorticoids.
Collectively, these data suggest that while VSG and RYGB result in equivalent improvements in metabolic parameters, these surgeries differentially affect the HPA axis. RYGB exhibit an overall increase in basal (non-stress) HPA axis activity. Differences between RYGB and VSG may be attributable to the altered milieu of circulating metabolic hormones that have differential patterns and levels of release following these surgeries.
Disclosure: RJS: Board Member, Johnson &Johnson, Investigator, Johnson &Johnson, Consultant, Novo Nordisk, Investigator, Novo Nordisk. SCB: Research Funding, Johnson &Johnson. Nothing to Disclose: BEG, APH, MK, HL, AEE, SCW, JPH, YMU
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