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dc.contributor.authorMunro, John Morley
dc.date.accessioned2010-06-10T01:51:25Z
dc.date.available2010-06-10T01:51:25Z
dc.date.issued1982
dc.identifier.urihttps://hdl.handle.net/10182/2021
dc.description.abstractThe ovine pancreas was studied to determine the yield of insulin, the effect of dietary treatments on insulin yield and factors which influence the secretion of insulin from the gland. Thus, pancreas glands were collected from lines of lambs from local freezing works, the insulin extracted and assayed. Results showed that the yields of insulin from New Zealand pancreatic glands were considerably higher (295 I.U. 100 g pancreatic tissue⁻¹) than first reported for glands exported and extracted for insulin in the U.S.A. (100 - 120 I.U. 100 g pancreatic tissue⁻¹). The procedure used to collect the pancreas glands and the age of the animal are probably responsible for the increased yields of insulin. In New Zealand, lucerne or white clover and ryegrass, the forages normally grazed by lambs, had little effect on pancreatic and plasma insulin levels. The pancreatic insulin levels could, however, be significantly increased (up to 520 I.U. 100 g⁻¹) by the lambs either grazing rape or being fed a concentrate diet based on maize. A close association was also found between pancreatic and plasma insulin levels in the lambs fed maize diets. Feeding only milk to lambs also increased the levels of plasma insulin and presumably the pancreatic insulin levels. It was clearly demonstrated that whenever exogenous glucose was available in the small intestine either by feeding maize, infusing glucose directly into the duodenum or by feeding milk, blood glucose levels were increased and associated with this, plasma insulin levels also increased. The high correlation between blood glucose and plasma insulin levels, in milk fed lambs, suggests that the absorption of dietary carbohydrate in these pre-ruminant animals controls the levels of plasma insulin. This relationship probably accounts for the high correlation between the intake of dietary lactose and the turnover of plasma glucose in milk fed lambs. In the grass fed lambs, however, there was little association between the intake of digestible organic matter and the turnover of plasma glucose. Similarly, in these animals, there was a poor correlation between the levels of plasma insulin and the intake of digestible organic matter. Furthermore, gut hormones were not apparently released from the duodeneum by the presence of exogenous glucose in the ruminant animal. It was concluded that in ruminants no single factor influences insulin secretion, however, as the animal obtains a greater proportion of its glucose from the diet, the regulation of insulin secretion moves towards that observed in the monogastric.en
dc.language.isoenen
dc.publisherLincoln College, University of Canterburyen
dc.rights.urihttps://researcharchive.lincoln.ac.nz/page/rights
dc.subjectovine pancreasen
dc.subjectinsulinen
dc.subjectsecretionen
dc.subjectpancreatic glandsen
dc.subjectdieten
dc.subjectruminant metabolismen
dc.titleFactors influencing insulin yield and secretion from the ovine pancreasen
dc.typeThesisen
thesis.degree.grantorUniversity of Canterburyen
thesis.degree.levelDoctoralen
thesis.degree.nameDoctor of Philosophyen
lu.thesis.supervisorBickerstaffe, Roy
lu.contributor.unitDepartment of Agricultural Sciencesen
dc.rights.accessRightsDigital thesis can be viewed by current staff and students of Lincoln University only. Print copy available for reading in Lincoln University Library. May be available through inter-library loan.en
dc.subject.anzsrc060603 Animal Physiology - Systemsen


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