Dual effects of hyperprolactinemia on carrageenan-induced inflammatory paw edema in rats

Objectives: The effects of short-term 5-day and long-term 30-day hyperprolactinemia induced by domperidone (1.7 mg/kg/day, s.c.) or ectopic pituitary graft on the acute inflammatory response induced by carrageenan were evaluated in male rats. Both models of hyperprolactinemia effectively increased serum Prolactin (PRL) levels.

Methods: The volume in milliliters of inflammatory edema was measured by plethysmography 1, 2, 3, 4, 6, 8 and 24 h after carrageenan injection. The areas under the inflammatory time-response curves were compared. Additionally, the effects of hyperprolactinemia on body weight and serum corticosterone levels were evaluated.

Results: In both domperidone-treated and pituitary graft-implanted Animals, short-term 5-day hyperprolactinemia increased the inflammatory response, while long-term 30-day hyperprolactinemia had anti-inflammatory effects. Body weight was not affected by either short- or long-term hyperprolactinemia.

Conclusion: These results show that PRL has biphasic effects on the carrageenan-induced inflammatory response.