Detection of Prolactin Receptor Gene Expression in the Sheep Pituitary Gland and Visualization of the Specific Translation of the Signal in Gonadotrophs

• DOI: 10.1210/endo.139.12.6365
• Publication Date: 2014-01-08T16:09:14Z
• Authors: Domingo J. Tortonese; Julie Brooks; Patricia M. Ingleton; Alan S. McNeilly
• Keywords: Prolactin receptor; Northern blot; Gonadotropin

In sheep, as in other mammalian species, the pronounced reduction GnRH and gonadotropin secretion that characterizes stages of infertility is normally associated with a conspicuous increase PRL. A possible role PRL modulating release implies presence activation specific receptors target tissues (i.e. pituitary, hypothalamus). this study, we investigated expression receptor (PRL-R) messenger RNA (mRNA) sheep pituitary distribution translated product cell types. Using primers designed to flank different regions extracellular cytoplasmic domains PRL-R, two complementary DNA (cDNA) fragments, one which was for long-form were amplified by reverse transcriptase-PCR. Sequencing revealed more than 95% identity nucleotides 267-1272 bovine PRL-R cDNA. When these cDNA fragments used probes detection mRNA Northern analysis, three major transcripts approximately 13, 10, 3.5 kb identified pituitary. Both detected identical transcripts, suggesting primarily long form expressed gland. No difference abundance observed between anestrous breeding season ewes (P > 0.05). Additional RT-PCR studies existence variant bearing 39-bp insert premature stop codon. Translation confirmed Western blot analysis. The identification types carried out immunocytochemistry. Double immunofluorescent staining, using antibodies rat liver monoclonal LHbeta-subunit, FSHbeta-subunit, free alpha-subunit, PRL, or GH, both pars distalis tuberalis, all cells expressing immunoreactivity positive LHbeta, although only 53% LHbeta-positive PRL-R. small proportion (2%) gonadotrophs negative FSHbeta, indicating localization LH (or LH/FSH) secreting cells. Further, selective cytological association where appeared surrounded lactotrophs. contrast observations, completely absent lactotrophs vast majority (>98%) somatotrophs. conclusion, here show translation signal gonadotrophs. These results support hypothesis may be involved regulation through paracrine mechanism within gland action does not seem mediated changes expression.