title: Targeted ablation of gonadotrophs in transgenic mice depresses prolactin but not growth hormone gene expression at birth as measured by quantitative mRNA detection.
abstract: We previously reported that transgenic ablation of gonadotrophs results in impaired development of cells immunostainable for prolactin (PRL) but not of cells immunostainable for growth hormone (GH) or pro-opiomelanocortin (POMC) in pituitary of newborn mice. The question remained whether this reduction in PRL protein is a reflection of reduced PRL mRNA expression, or whether this regulation is only situated at the translational level. We therefore generated a new series of transgenic mice in which gonadotrophs were ablated by diphtheria toxin A targeting, and analyzed hormone mRNA levels instead of hormone protein around the day of birth. Pituitary mRNA expression levels of luteinizing hormone-beta (LHbeta), PRL and GH were quantified using real-time TaqMan RT-PCR. Of the 13 transgenic mice obtained, 8 showed a clear-cut reduction (ranging from 62 to 98%) in LHbeta mRNA levels. PRL mRNA values were significantly reduced in the transgenic mice (p = 0.0034), while GH mRNA expression was unaffected (p = 0.93). An additional observation was that female newborn mice produce 5 times more LHbeta mRNA than male mice whereas no sex difference was observed for expression levels of PRL and GH mRNA. Moreover, in the wild-type mice, LHbeta mRNA expression was 20-fold higher than GH mRNA expression which in turn was 500- to 1,000-fold higher than PRL mRNA expression, suggesting a low expression level of the PRL gene at birth. In conclusion, the present data support the hypothesis that embryonic development of PRL gene expression is stimulated by gonadotrophs.
authors: Department of Molecular Cell Biology, Laboratory of Cell Pharmacology, University of Leuven (K.U. Leuven), Medical School, Campus Gasthuisberg (O & N), BE-3000 Leuven, Belgium. Hugo.Vankelecom@med.kuleuven.ac.be
authors: Hugo
authors: H
authors: Vankelecom
authors: Eve
authors: E
authors: Seuntjens
authors: Annelies
authors: A
authors: Hauspie
authors: Carl
authors: C
authors: Denef
mesh_terms: D000818:Animals; D017931:DNA Primers; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D013006:Growth Hormone / Q000235:genetics / Q000502:physiology*; D007986:Luteinizing Hormone / Q000235:genetics / Q000502:physiology; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D019899:Paracrine Communication; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D011388:Prolactin / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D011388:Prolactin; D007986:Luteinizing Hormone; D013006:Growth Hormone