POUL 4060 Lecture Notes - Lecture 14: Anterior Pituitary, Prolactin, Positive Feedback
15 Apr 2019
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Document Summary
*last hormone of the semester: protein hormone produced by anterior pituitary, secretion under stimulatory control of vip. Increases at the onset of egg laying: light stimulates hypothalamus to produce vip which then stimulates the anterior pituitary to produce prolactin. In temperature zones, light stimulates onset of prolactin production in long day breeders. In most bird species, prolactin levels higher in the sex that invests more in parental duties: higher in males if male is incubating eggs. If both sex are sharing parental duties, prolactin is equal. It reduces circulating concentrations of fsh and lh which results in ovarian regression. Increases nesting activity and gets rid of fsh and lh and the sex hormones so the birds aren"t receiving signals for copulation. Rather, they are receiving signals for incubation and parental care: with sex steroids induces incubation behavior, e2 primes vip/prl system, p4 persistent nesting behavior, positive feedback, want prolactin to peak at time of incubation.
