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Stress causes the activation of both the hypothalamic-pituitary-adrenocortical axis and sympatho-adrenal system, thus leading to the release from the adrenal medulla of catecholamines: adrenaline and, to a lesser degree, noradrenaline. It has been established that in addition to catecholamines, the adrenomedullary cells produce a variety of neuropeptides, including corticoliberine (CRH), vasopressin (AVP), oxytocin (OXY) and proopiomelanocortine (POMC) -a precursor of the adrenocorticotropic hormone (ACTH). The aim of this study was to investigate adrenal medulla activity in vitro depending, on a dose of CRH, AVP and OXY on adrenaline and noradrenaline release. Pieces of sheep adrenal medulla tissue (about 50 mg) were put on 24-well plates and were incubated in 1 mL of Eagle medium without hormone (control) or supplemented only once with CRH, AVP and OXY in three doses (10 -7 , 10 -8 and 10 -9 M) in a volume of 10 μL. The results showed that CRH stimulates adrenaline and noradrenaline release from the adrenal medulla tissue. The stimulating influence of AVP on adrenaline release was visible after the application of the two lower doses of this neuropeptide; however, AVP reduced noradrenaline release from the adrenal medulla tissue. A strong, inhibitory OXY effect on catecholamine release was observed, regardless of the dose of this hormone. Our results indicate the important role of OXY in the inhibition of adrenal gland activity and thus a better adaptation to stress on the adrenal gland level.

B£ACHUTA M., WROÑSKA-FORTUNA D. 2012. Changes in estrogen receptor ERá and ERâ expression in chicken (Gallus domesticus) adrenal gland during short-fasting and refeeding.Folia Biologica (Kraków) 60: 199-203. Estrogen receptors have been found in the adrenal gland of rodents, monkeys, mares and sheep, indicating a connection between sex steroids and the activity of the adrenal gland. In the present study, the expression of estrogen receptors alpha (ERá) and beta (ERâ) in the chicken adrenal gland during stress induced by 24 h fasting and after refeeding was determined using reverse transcription and the polymerase chain reaction (RT-PCR). The presence of both ER mRNAs in the adrenal gland of all examined groups was found. The relative expression of ERá mRNA was higher than ERâ mRNA. There were no significant differences in ERá mRNA expression among the examined groups. On the contrary, we observed changes in ERâ expression during stress conditions. These findings indicate different pathways of estrogen action in the avian adrenal gland. Furthermore, changes in ERâ level suggest that this form of estrogen receptor plays a predominant role for estrogen action in the chicken adrenal gland during stress.

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