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Prolactin (PRL) is a highly versatile hormone in terms of its biological functions. In Galliformes, high levels of PRL are associated with incubation behaviour and hatching. It has been shown that these high levels of PRL were associated with an increased ratio of glycosylated PRL (G-PRL) versus non-glycosylated PRL (NG-PRL) in turkey (Bedecarrats et al., 1999a). This suggests that glycosylation of PRL is related to its proper function during those stages of life. However, the mechanism(s) controlling post-translational modification of PRL are unknown. In order to investigate genes associated with the glycosylation of PRL, an in vitro study was undertaken. The pituitary glands of day 24 turkey embryos (n=60) were collected and pooled into two groups which were incubated in medium 199 for 4 hours in the absence or presence of 10-7 M vasoactive intestinal peptide (VIP). Western blot analysis of PRL was used to assess the response of the pituitary glands to the VIP stimulation. As expected, the absolute level of PRL as well as the percentage of glycosylated PRL isoform increased following stimulation with VIP. The mRNA of both stimulated and non-stimulated samples were extracted and reverse transcribed into cDNA. Using suppression subtractive hybridization (SSH), a cDNA subtractive library which only contained differentially expressed cDNAs between VIP stimulated and non-VIP stimulated turkey pituitary glands was constructed. Seventeen percent of the genes from the library are related to cell proliferation and apoptosis. Ten genes were selected for real-time PCR analysis. The functions of these genes and their potential roles in response to the stimulation by VIP and glycosylation of PRL are discussed.

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Prolactin receptor (PRLR) is a membrane anchored protein mediating the biological actions of prolactin. The turkey PRLR (tPRLR) cDNA was isolated and characterized. The open reading frame (ORF) of tPRLR predicted 831 amino acid residues composed of a signal peptide, an extracellular domain (ECD), a single transmembrane domain and an intracellular domain. The deduced amino acid sequence of the turkey prolactin receptor is 53.8%, 51.7%, 49.8%, 49.8%, 80.3% and 89.91% identical to that of the rabbit bovine, human, long form of the rat, pigeon and chicken PRLRs, respectively. The extracellular domain contains two homologous repeat units with 63% amino acid sequence identity to each other. The membrane-distal and membrane-proximal repeats were 53--60% and 62--70% identical to the ECDs of the mammalian PRLRs, respectively. A tPRLR transcript with a molecular size of 3 kilo nucleotides was identified and was detectable in 26 tissues examined. The pituitary gland, crop sac, duodenum and gizzard were found to express the highest levels of tPRLR mRNA among the 26 tissues. In most tissues examined there was no obvious relationship between blood levels of PRL, reproductive states and estimated concentrations of the receptor mRNA. However, in the hypothalamus, increasing blood levels of PRL were associated with decreasing levels of receptor transcripts (p < 0.05), whereas, the opposite relationship was observed in the pituitary gland (p < 0.05). The extracellular domain of tPRLR (tPRLR-ECD) was expressed as a GST fusion protein (tPRLR-ECD-GST) in E. coli. The expression of tPRLR-ECD-GST in BL21 strain yielded a protein with a molecular mass of 76 kDa. About 99% of the fusion protein was present in inclusion bodies and about 50% of the total protein in inclusion bodies was the fusion protein. The insoluble fusion protein was denatured, refolded and purified using GST affinity chromatography. The yield of the purified fusion protein was 20 mg per liter with an estimated p

Thesis (M.S.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains viii, 81 p. : ill. Vita. Includes abstract. Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xvii, 154 p.; also includes graphics (some col.) Includes bibliographical references (p. 134-154). Available online via OhioLINK's ETD Center

Thesis (M.S.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Missouri--Columbia, 1999. / "December 1999." Typescript. Vita. Includes bibliographical references (leaves 171-188). Also available on the Internet.