|Carroll, Jeffery - Jeff Carroll|
Submitted to: American Society of Animal Science Southern Section Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 1/27/2001
Publication Date: N/A
Technical Abstract: This study examined relationships among components of the adrenal axis during activation of the systemic inflammatory response syndrome (SIRS) in neonatal pigs. We previously reported that administration of E. Coli to pubertal and neonatal pigs stimulates secretion of tumor necrosis factor alpha, ACTH, and cortisol. The rate-limiting step in adrenal gland synthesis of cortisol is controlled by the steroidogenic acute regulatory (StAR) protein. To study the effects of an oral E. Coli challenge on StAR protein production, 20 crossbred pigs (n=10 males and 10 females, 14 d, 5.6 kg) were weaned into individual pens and randomly assigned to one of two treatments (n=5/sex/treatment): Control (C; 5 ml sterile culture media) or E. Coli (EC; 5 ml of Eschericia coli F17, 100 million CFU/ml). On d 6 postweaning, all pigs were non-surgically fitted with jugular cannulae. On d 7, an oral dose of either sterile media or E. Coli was given followed by serial blood samples for 10 h. Pigs were then humanely sacrificed for tissue collection. Adrenal samples were used in Western blot procedures to determine StAR content. Plasma ACTH and CS did not differ between C and EC pigs prior to EC challenge. A time x EC x sex interaction (P<.014) was observed for serum ACTH and CS such that females had a greater response to the EC than males. Likewise, there was a EC x sex interaction (P<.012) for adrenal production of StAR such that EC increased StAR production in females but not males. Adrenal StAR content was not significantly correlated with ACTH or CS parameters in C pigs; however, adrenal StAR was highly correlated with plasma ACTH (r=.75, P<.02) and plasma CS (r=.80, P<.007). These observations demonstrate a positive relationship of ACTH, StAR protein and CS during SIRS.