Expression Profiles of Prolactin Receptors during Chicken Embryonic Development

Abstract

Prolactin (PRL) interacts with prolactin receptor (PRLR) in a broad variety of target tissues to exert diverse physiological functions in vertebrates. In order to elucidate the physiological roles of prolactin in chicken embryonic development, we have examined the expression profiles of prolactin receptor by semiquantitative reverse transcription-polymerase chain reaction (semi-quantitative RT-PCR). On day 8 of chicken embryos, the prolactin receptor mRNA could be easily detected in allantoic membrane, intestine, kidney, liver, lung, heart, brain, and anterior pituitary. Interestingly, during embryonic development (from day 8 to day 20 of incubation), the expression levels of prolactin receptor mRNA in all tissues examined were maintained at a high level, which is comparable to those in adult chicken tissues. By contrast, the levels of prolactin mRNA expression on day 8 in the anterior pituitary were very low and the maximal expression was detected on day 20. The differential expression patterns of prolactin and prolactin receptor mRNA during chicken embryonic development demonstrate that pituitary prolactin plays roles in the late development of chicken embryos and further suggest that prolactin receptor may be involved in early embryonic development.