Abstract
Much evidence indicates that dopamine can inhibit PRL secretion. However, it is still unclear whether dopamine acts on hypothalamic neurons to stimulate PRL-inhibiting factor (PIF) release or whether dopamine is itself PIF, acting directly on the pituitary. This study was designed to determine if PRL secretion is inhibited by dopamine infusions producing plasma dopamine levels which mimic those found in hypophysial stalk plasma. Stalk plasma dopamine concentration in urethane-anesthetized diestrus-1 rats was 6.0 ± 1.1 ng/ml (mean ± SE; n = 10). During a dopamine infusion, stalk plasma dopamine levels were 70% of arterial levels. Therefore, dopamine was infused at a rate which achieved arterial levels of 9–10 ng/ml and the effect on PRL secretion in urethane-anesthetized female rats was measured. In diestrus rats, dopamine did not inhibit PRL secretion. In rats pretreated with α-methyl-p-tyrosine to elevate serum PRL levels, dopamine suppressed PRL secretion 70%. In rats with PRL levels elevated by median ...
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
