A priming effect of LH-RH on the pituitary in rams

Abstract
The mean LH [luteinizing hormone] response to the 2nd injection of LH-RH [LH-releasing hormone] was significantly (P < 0.01) greater than the response to the 1st. The 5 experimental animals showed the same pattern of response, but the sensitivity of individual animals to the treatment differed. When the 1st injection of LH-RH was replaced by saline in the control rams the response to LH-RH administered i.v. to the ram has the dual action of releasing some LH and sensitizing the pituitary so that greater amounts of LH are released by a 2nd dose of LH-RH 1 h later.