Naslov
Opposite effects of isoproterenol on cAMP levels in rat adrenal cortices before and after unilateral adrenalectomy

Autori
Sečić, Helena ; Trkulja, Vladimir ; Barač, Ana ; Lacković, Zdravko

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Program & Abstracts 1st International Conference on Signal Transduction / Đikić, Ivan ; Pavelić, Krešimir, Schlessinger Joseph - Zagreb : Ludwig Institute, Sweden; Institut Ruđer Bošković, Zagreb, HAZU, 1998, 77-77

Skup
1st International Conference on signal transduction

Mjesto i datum
Cavtat, Hrvatska, 08.10.1998. - 11.10.1998

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
adrenal gland; compensatory growth; adrenergic receptors; cAMP signalling

Sažetak
In the adrenal cortex beta-adrenergic receptors have been shown to be involved in the regulation of several endocrine functions. In the presented experiments, cAMP levels in rat adrenal cortices incubated with the beta-adrenoceptor agonist isoproterenol (100 uM at 37 °C for 7 min.) were elevated, as expected. This increase was fully abolished with three tested beta-adrenergic antagonists of different beta receptor selectivity, i.e., propranolol, atenolol and butoxamine, which indicated that both beta1 and beta 2 receptors are involved in the activation of adenylyl cyclase. Exposure to isporterenol, however, produced unexpected effects on cortical cAMP levles in dadrenals remaining after unilateral adrenalectomy: as measured 20 minutes and 2 hours after the operation, no difference in cAMP concentrations was found between adrenalectomized and sham operated animals, while after 2, 6, and 10 days cAMP levels were significantly lower tha in the operated groups. This effect of isoproterenol could be antagonized by butoxamine, but not by atenolol, indicating probable involvement of beta2 rather than beta1 receptors. From presented results we conclude that after unilateral adrenalectomy beta2 receptors change their effect on adenylyl cyclase signalling in the contralateral adrenal cortex. It is known that the adrenergic system is necessary for compensatory growth of the remnaining gland after unilateral adrenalectomy. In a series of experiments we found that chemical or surgical sympathectomy, as well as butoxamine aboilished compensatory adrenal growth, while isoproterenol and salbutamol had a stimulatory effect. Moreover, isproterenol or salbutamol reversed the effect of chemical sympathectomy or butoxamine. Thus, it seems that adrenergic stiumaltion of compensatory adrenal growth involves beta2 receptors. Altogether there results suggest that a beta2-adrenoceptor-mediated inhibition of adenylyl cyclase might be related to the beta2-adrenoceptor-mediated stimulation of compensatory adrenal growth.

Izvorni jezik
Engleski

Znanstvena područja
Kliničke medicinske znanosti

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