Receptor internalization, prolactin

Fig. 1. A model for the control of the luteinizing hormone receptor. LH interacts with a specific receptor (RLh) in Leydig cells which results in the activation of several transducing systems. This is followed by an uncoupling (desensitization) from one or more of the transducing systems. The latter may transiently remain active. The LH receptor complex is internalized and then dissociated in endocytic vesicles. LH is degraded in the lysosomes. The LH receptor synthesis can be controlled by several hormones including oestradiol, prolactin and growth hormone.

The interaction of factors regulating levels of prolactin receptors [26,56] in a variety of tissues is complex and not fully understood. The topic will not be considered in detail here. The actions of prolactin itself on the process will be discussed briefly, however. In the short term, prolactin often leads to down-regulation of its own receptors, presumably as a consequence of internalization following binding of... 

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