Prolactin and contact sensitivity.

Hypophysectomized (Hypo-X) rats did not develop contact dermatitis in response to dinitrochlorobenzene (DNCB). Syngeneic pituitary grafts placed under the kidney capsule or daily treatment with prolactin restored the DNCB-reactivity of Hypo-X animals. Combined treatment with other pituitary hormones was ineffective. Treatment of normal rats with a potent prolactin antagonist drug, bromocriptine, was as effective in inhibiting contact sensitivity as was hypophysectomy. These results indicate the contact sensitivity is a prolactin dependent reaction.