Role of splanchnic nerve on steroid-hormone-induced alteration of adrenomedullary catecholamines in untreated and reserpinized pigeon.

The aim of the present investigation was to ascertain (1) the effect of steroid hormones (corticosterone, dexamethasone, deoxycorticosterone, progesterone, testosterone and oestrogen) on the neural regulation of adrenomedullary catecholamine (CA) content, and (2) the neural modulation of the effect of glucocorticoid hormones (corticosterone and dexamethasone) on reserpine-induced resynthesis of CA. The experiment was conducted on unilaterally splanchnic-denervated pigeons. The findings revealed that 7 consecutive days of steroid treatments (2.5 mg.kg b.w.-1, i.m.) resulted in significant changes of CA content. Interestingly, the changes of epinephrine (E) content differed significantly between the innervated and denervated glands. This clearly indicates that the splanchnic nerve regulates steroid-induced alterations of E content in the pigeon. The results further revealed that the glucocorticoid hormones augmented reserpine-induced resynthesis of CA specifically in the innervated glands. This confirms that the splanchnic nerve is essential for the synergistic action of glucocorticoids and reserpine in accelerating resynthesis of CA.