Relative and Combined Effects of Estradiol and Prolactin on Corticosterone Secretion in Ovariectomized Rats

Ming-Jae Lo ； Paulus S. Wang

《The Chinese Journal of Physiology》 46卷3期 (2003/09) Pp. 103-109

並列摘要

In vivo and in vitro experiments were designed to assess the relationship of the estradiol (E2) and prolactin (PRL) on glucocorticoid secretion in ovariectomized (Ovx) rats. Female rats were Ovx for two weeks and then subcutaneously injected with oil or estradiol benzoate (EB) for 3 days before experimentation. Venous blood samples were collected from right jugular vein at 0, 30, 60, 90, and 120 min after challenge with adrenocorticotropin (ACTH). Adrenal zona fasciculata-reticularis (ZFR) cells from Ovx rats were isolated and incubated with E2 or PRL. In the morning and afternoon, EB enhanced the basal and ACTH-stimulated concentrations of plasma corticosterone (CORT) and PRL. Administration of E2 in vitro increased the basal and ACTH-stimulated release of CORT and production of adenosine 3', 5'-cyclic monophosphate (cAMP) in ZFR cells. E2 enhanced the forskolin-stimulated release of CORT by ZFR cells. However, the 3-isobutyl-l-methylxanthine (IBMX)- or 8-Br-cAMPstimulated release of CORT was not affected by E2. E2 augmented the lower doses of PRL-stimulated release of CORT and cAMP accumulation as compared with the PRL-treated group alone. Incubation of higher doses of PRL increased the production of cAMP. Administration of nifedipine and R(+) BK8644 (classic L-type Ca2+ channel blocker) significantly attenuated the PRL-stimulated release of CORT. Taken together, these data indicate that E2- and PRL-related increase of CORT in Ovx rats is associated with the increase of cAMP accumulation and calcium influx in ZFR cells. In conclusion, E2 and PRL play a stimulatory role in the co-regulation of CORT secretion.

並列關鍵字

E2 ； PRL ； corticosterone ； L-type Ca2+ channel ； cAMP ； ZFR cells

參考文獻

Barrett, P. Q.,Isales, C. M.,Bollag, W. B.,McCarthy, R. T.(1991).Modulation of Ca2+ channels by atrial natiuretic peptide in the bovine adrenal glomerulosa cell.Can. J. Physiol. Pharmacol.69,1553-1560.

Burleson, M. H.,Malarkey, W. B.,Cacioppo, J. T.,Poehlmann, K. M.,Kiecolt-Glaser, J. K.,Berntson, G. G.,Glaser, R.(1998).Postmenopausal hormone replacement: effects on autonomic, neuroendocrine, and immune reactivity to brief psychological stressors.Psychosom. Med.60,17-25.

Burgess, L. H.,Handa, R. J.(1992).Chronic estrogen-induced a alterations in adrenocorticotropin and corticosterone secretion, and glucocorticoid receptor mediated function in female rats.Endocrinology.131,1261-1269.

Cagnacci, A.,Soldani, R.,Yen, S. S.(1997).Melatonin enhances cortisol levels in aged women: reversible by estrogens.J. Pineal Res.22,81-85.

Chang, L. L.,Lo, M. J.,Kan, S. F.,Huang, W. J. S.,Chen, J. J.,Kau, M. M.,Wang, J.L.,Lin, H.,Tsai, S. C.,Chaio, Y. C.,Yeh, J. Y.,Wun, W. S. A.,Wang, P. S.(1999).Direct effects of prolactin on corticosterone release by zona fasciculata-reticularis cells in ovariectomized rats.J. Cell. Biochem.73,563-572.