Dose-dependent Effects of a Glucocorticoid on Prolactin Production

Endocrine Journal

Sukumar DEVNATH³  Chihiro MOGI¹  Yoshihiro SASAKAWA⁴  Mahoko HAYASHI³  Kotaro YOKOYAMA³  Gen WATANABE²  Kazuyoshi TAYA²  Kinji INOUE³ 

[1] Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University;Laboratory of Veterinary Physiology, Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology;Graduate School of Science and Engineering, Saitama University;Laboratory of Veterinary Ethology, Graduate School of Agricultural and Life Sciences, University of Tokyo

关键词: Pituitary;    Prolactin;    Glucocorticoid;    Estrogen;    Somatomammotrope;   

DOI  :  10.1507/endocrj.K07E-063

学科分类：内分泌与代谢学

来源: Japan Endocrine Society

【 摘 要 】

References(27)Cited-By(4)Glucocorticoids are known to stimulate growth hormone (GH) production but to suppress prolactin (PRL) production. However, previous data were obtained with rather high doses of corticosterone. In this study we examined the effects of various doses (10 -12 -10 -7 M) of corticosterone on GH and PRL production in a rat pituitary somatomammotropic cell line, MtT/SM cells, and found that GH mRNA expression was facilitated by high doses (10 -7 and 10 -8 M). In contrast, a biphasic effect of corticosterone on PRL mRNA expression and secretion was observed, i.e., high doses (10 -7 and 10 -8 M) suppressed and low doses (10 -12 -10 -10 M) facilitated them. In an immunofluorescent staining study, the number of PRL immunopositive cells increased with low doses of corticosterone while it decreased with high doses of it, which corresponded to PRL mRNA expression and hormone secretion, respectively. These effects of corticosterone on PRL production were abolished by a glucocorticoid receptor (GR) antagonist, mifepristone. In addition, co-treatment with low doses of corticosterone (10 -12 -10 -10 M) and 17β-estradiol (E2, 10 nM) additively increased the number of PRL immunopositive cells. Moreover, a 24 h BrdU incorporation experiment suggested that the increase in the number of PRL immunopositive cells treated with low dose corticosterone was caused by novel synthesis of PRL while, on the other hand, that of those treated with E2 resulted from PRL cell proliferation. Thus, we concluded that corticosterone biphasically regulates PRL production and the sensitivity of E2 to different degrees.

【 授权许可】

Unknown