In many species a developmentally related increase in cortisol production from the fetal adrenal gland brings about the progressive maturation of fetal organ systems and triggers the onset of parturition. The fetal hypothalamus is thought to play a pivotal role in this process by secreting the neuropeptides, CRH and AVP which act upon the fetal pituitary gland to cause the secretion of ACTH. However, little is known about the ontogeny and neuroendocrine regulation of CRH and AVP secretion from the fetal hypothalamus. The experiments described in this thesis were therefore designed to investigate the maturation of CRH and AVP secretion from the fetal hypothalamus during fetal development. In order to study the secretion on CRH and AVP from the fetal hypothalamus a method for the serum-free culture of fetal sheep hypothalamic neurones was developed. The system was optimised in terms of plating density and substrate requirements and cells were maintained in vitro for up to 35 days. The functional capacity of these cells was demonstrated by measuring enhanced AVP secretion after potassium-induced depolarization, a response which was time- and calcium-dependent. To investigate the ontogeny of CRH and AVP secretion, cultured fetal sheep hypothalami removed at day 70, day 100 and day 130 of gestation (Term = day 145) were incubated with control and 56 mM potassium-containing medium. The results showed an overall reduction in basal and potassium-stimulated CRH and AVP release with advancing gestational age. These data suggested that hypothalamic secretion of CRH and AVP was reduced with advancing gestation.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:649040 |
| Date | January 1992 |
| Creators | Currie, Ian Stewart |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/19665 |
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