Further evidence for the involvement of prolactin in the inflammatory response.

The pro-inflammatory activity of prolactin (PRL) was clearly demonstrated in our previous research on rat paw oedema. In the present study we report our results on the activity of PRL on other animal models of acute and chronic inflammation. Repeated administration of ovine PRL provoked a significant increase in the inflammatory parameters in experimental carrageenan pleurisy (leukocytes number and prostaglandin E2 concentration in the exudate). A pro-inflammatory effect was also present after a hyperprolactinaemia induced by pituitary gland graft. Moreover, the inflammatory response to polyester sponge implantation was significantly potentiated by oPRL, whereas the hormone was completely inactive on cotton pellet granuloma test. A possible involvement of prostaglandins in the pro-inflammatory activity of PRL is suggested.