Changes in the responsiveness of hen anterior pituitary to cLHRH-II during induced molting

The goal of this study was to determine whether the responsiveness of the anterior pituitary to cLHRH-II in relation to luteinizing hormone-β subunit (LHβ) mRNA expression is improved by induced molting. White Leghorn hens were subjected to induced molting by feed withdrawal for 4 days. The anterior pituitaries were collected from hens of pretreatment (PT), 1 day after resumption of feeding (1DRF) and on the day of resumption of laying (RL). They were processed for organ culture in the medium with or without cLHRH-II, followed by reverse transcription and competitive PCR. When pituitary tissues were incubated without cLHRH-II, the expression of LHβ mRNA did not show any significant difference between PT and RL group hens. In contrast, the expression of LHβ mRNA in the pituitaries that were incubated with cLHRH-II was significantly greater in RL group hens than those in PT and 1DRF groups. Among PT, 1DRF, and RL groups only RL hens showed significant increase of LHβ mRNA synthesis when compared with control (without cLHRH-II). These results suggest that the responsiveness of the anterior pituitary to cLHRH-II increased in postmolt hens, indicating that the functions of this organ might be improved by induced molting.