Direct Effect of Prolactin on Adrenal Steroidogenesis and It's Mechanism
Date Issued
2006
Date
2006
Author(s)
Chen, Yun-Ru
DOI
zh-TW
Abstract
Prolactin (PRL) is a 23 kDa protein hormone closely related to growth hormone. It is secreted by lactotrophs in the anterior pituitary and primarily functions to enhance breast development during pregnancy and to induce lactation. Hyperprolactinemia, a condition of abnormal elevation in the serum PRL level caused by differential physiologic conditions, is frequently associated with hirsutism, hypogonadism, and amenorrhea due to anomalous adrenal and gonadal functions. Since the expression of PRL receptor has been detected by immunohistochemistry and RT-PCR in the human adrenal glands, it is speculated that PRL has a direct effect on adrenals. In this study, we want to investigate the function of PRL on adrenal steroid biosynthesis and its mechanism.
We used the human adrenocortical NCI-H295 cell line as the model. After treated with PRL, the culture medium was collected and detected by ELISA. The administration of PRL stimulated progesterone (P4) and crotisol (F) secretion of the cells in several minutes. The induction of P450scc protein amount and StAR mRNA amount were detected with Western Blotting and RT-PCR, respectively.
Specific inhibitors of JAK2, MEK/ERK1/2 and PKA were used to study the signal pathways of PRL. The acute induction on steroid secretion was reduced by all three inhibitors. Interestingly, both inhibitors of JAK2 and PKA reduced PRL-induced P450scc protein amount, but MEK/ERK1/2 inhibitor did not. Obviously, PRL activates P450scc expression via signaling pathway of JAK2 and PKA and an unknown steroidogenic protein via MEK/ERK1/2 to stimulate adrenal steroidogenesis.
Subjects
泌乳素
腎上腺
類固醇生合成
訊息傳遞途徑
膽固醇側鏈截切酵素
類固醇生成急性調控蛋白
Prolactin
Adrenal
Steroidogenesis
Signal Pathway
P450scc
StAR
Type
thesis
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