This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

Changes in the pituitary content of prolactin (PRL) and in the ratio of immunoreactive forms of PRL were measured during a reproductive cycle in turkey hens. Low levels of PRL were observed in pituitary glands from sexually immature, out-of-lay and moulting hens. Higher levels were present during the egg laying period and the highest levels were detected in hens expressing incubating behaviour. Two immunoreactive bands of apparent molecular weights of 24 and 27 kDa were visualised on western blots, corresponding to the non-glycosylated (NG-) and glycosylated (G-) forms of PRL, respectively. The percentage of G-PRL was about 60 in sexually immature and egg laying hens. In pituitaries from incubating, out-of-lay and moulting hens the percentage of G-PRL was about 70, 38 and 33, respectively. Thus, higher percentages of G-isoforms (27 kDa) were associated with high levels of total PRL and Iower percentages were associated with low levels of PRL content in the pituitary gland. Digestion of the isoforms with N-glycosidase F resulted in a single band with an apparent molecular weight of 24 kDa. Partial deglycosylation was achieved using neuraminidase, whereas digestion with O-glycosidase had no apparent effect on the isoforms. Thus, G-PRL has N-linked carbohydrates containing sialic acid. In order to study the in vitro release of the PRL isoforms, pituitary glands from turkeys at various physiological stages were stimulated by cVIP in a perifusion system. Total PRL content and the ratio of immunoreactive PRL isoforms in the perifusate were monitored. All the perifused pituitaries responded to cVIP stimulation by increasing the release of PRL. Two immunoreactive bands corresponding to the ones detected in pituitary extracts were detected by western blotting. The G-PRL (27 kDa) was predominant in samples from egg laying and incubating hens and the NG-PRL (24 kDa) was predominant in samples from out-of-lay and moulting hens. No change in the ratio of isoforms released was / A competitive reverse transcription polymerase chain reaction assay was developed in order to semi-quantify the PRL mRNA in individual pituitary glands from turkey embryos and poults. Pituitary content and plasma levels of PRL were also monitored, and the PRL isoforms present in the pituitary gland were detected. The levels of PRL mRNA remained low until five days before hatching, increased until the day of hatch, plateaued during the first three days of age and significantly increased at two weeks of age. Similar changes were observed in pituitary content and plasma concentrations of PRL which were highly correlated. Two immunoreactive bands corresponding to the NG- and G-PRL detected in adult pituitary gland were visualised on western blots. The percentage of G-PRL in pituitary glands were 31.5, 48.6, 48.0 and 56.2 at 22 and 27 days of incubation and at I and 7 days of age, respectively. Thus, higher percentages of G-PRL (27 kDa) were associated with higher levels of total PRL in the pituitary gland.

Changes in the levels of expression of the prolactin receptor (PRLR) mRNA in the pituitary gland, hypothalamus, liver, pancreas, kidney and gonad from embryonic day (ED) 15 and ED21 to 1 day post-hatch, respectively, in chickens and turkeys were measured by real-time PCR. In both species, PRLR mRNA increased from low levels during the last week of ED to reach maxima at the peri-hatch period. Similarly, circulating levels of prolactin (PRL) also increased during this interval and were correlated with the observed increases in tissue content of PRLR mRNA. This suggested that PRL was up-regulating its own receptor during late embryogenesis. In support of this, in vitro stimulation of the pituitary gland of turkeys with VIP on ED24 resulted in a 4 fold and 3 fold increase in PRL and PRLR, respectively. Stimulation with VIP of either the hypothalamus or gonad had no effect on either levels of the PRLR transcript. This suggests that VIP acts indirectly through increased PRL to upregulate the number of receptors. In order to investigate the transcription of genes that may be induced/suppressed by PRL, suppressive subtractive hybridization (SSH) libraries from control or VIP stimulated ED24 turkey pituitary glands were constructed. Stimulation with VIP resulted in a 5.7 and 2.8 fold increase in media and pituitary content of PRL, respectively. The changes in PRL were consistent with endogenous levels of PRL observed just prior to hatch. Following sequence analysis of random clones (n=96) from each library, a total of 145 non-redundant putative genes were obtained. About 51% of the putative genes have as yet no assigned function, whereas, 15% were housekeeping genes and 34% had known functions within various pathways. Real-time PCR was used to confirm the differential expression of 21 of these genes in VIP treated and control pituitaries. Since the majority of these genes were expressed at levels consistent with the direction of subtraction, these data suggest that these libraries may be useful to study the direct and indirect effects of increasing levels of PRL on anterior pituitary function at about the time of hatch.

No description available.

Thesis (Ph.D.)--Michigan State University. Dept. of Food Science and Human Nutrition, 2008. / Title from PDF t.p. (viewed on Mar. 27, 2009) Includes bibliographical references (p.108-118). Also issued in print.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1963. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Vita. Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

No description available.