Mechanisms of Dopamine Action on the Lactotroph

摘要: Prolactin (PRL) is a hormone with numerous functions: reproductive, immunological, growth, metabolic, and behavioral. The pattern of PRL release from the anterior pituitary gland changes during development differs between sexes. In female rat, dynamic, fluctuating rapidly normal physiological conditions. Episodic ofPRL occurs on afternoon proestrus (1,2), in pseudopregnancy (3), early pregnancy (4) response to suckling lactation (5). secretion appears be regulated complex manner by variety hormones neurotransmitters (for reviews: 6,7). Inhibition secretion, major regulatory influence hypothalamus, mediated primarily dopamine (DA). This DA released tuberoinfundibular neurons terminating median eminence delivered via hypophyseal portal vessels 8,9). PRL, turn, believed feed back hypothalamic regulate ofDA and, ultimately, its own (10,11). There exists an extensive list substances that demonstrate stimulatory action 6,7,9). However, demonstration role for any these secretagogues has remained elusive. What clear, normally under tonic inhibition periodic, surges females require withdrawal this dopaminergic inhibition.