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Hormone and neurotransmitter receptor studies in the rat during pregnancy and the postpartum period
Thesis (Ph.D.(Medicine)) -- University of Stellenbosch, 1991.
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : Stellenbosch University
2012
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| _version_ | 1867613744085860353 |
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| access_status_str | Open Access |
| author | Glaser, Jonathan |
| author2 | Taljaard, J. J. F. |
| author_browse | Glaser, Jonathan Taljaard, J. J. F. |
| author_facet | Taljaard, J. J. F. Glaser, Jonathan |
| author_sort | Glaser, Jonathan |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (Ph.D.(Medicine)) -- University of Stellenbosch, 1991. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/69269 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:41:00.180Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2012 |
| publishDateRange | 2012 |
| publishDateSort | 2012 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/69269 Hormone and neurotransmitter receptor studies in the rat during pregnancy and the postpartum period Glaser, Jonathan Taljaard, J. J. F. Russell, V. A. Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Pathology. Division of Chemical Pathology. Hormone receptors Neurotransmitter receptors Hormones Postpartum depression Dissertations -- Medicine Thesis (Ph.D.(Medicine)) -- University of Stellenbosch, 1991. Hormonal and neurochemical studies were performed in the rat during the estrous stage of the cycle, at 10, 15 and 20 days of pregnancy and at 2 and 4 days postpartum. A specific, sensitive (± 50 pg/assay tube) antiserum was produced in rabbits for the determination of plasma corticosterone levels. Plasma progesterone levels increased significantly during pregnancy with the highest level occurring in the 15 day pregnant group. At 4 days postpartum, the level of progesterone decreased significantly. Estradiol‑17β levels rose during pregnancy and reached the highest level at 20 days of pregnancy. Plasma corticosterone levels were significantly lower in the 4 day postpartum group than in the estrous, 15 and 20 day pregnant groups. The postpartum increase in noradrenaline (NA) concentration in the hypothalamus (a limbic brain area involved in endocrine function) and hippocampus (a limbic brain area involved in mood changes) was possibly due to a decrease in NA turnover, since the 3‑methoxy‑4‑hydroxyphenylglycol (MHPG) to NA ratio was decreased in postpartum rats. A decrease in dopamine (DA) was measured in the hypothalamus during pregnancy and corresponded with the finding of increased breakdown of DA measured in terms of increased 3,4‑dihydroxyphenylacetic acid (DOPAC) to DA ratios at 20 days of pregnancy relative to estrous levels. Striatal DA concentrations were increased postpartum, while homovanillic acid (HVA) and HVA/DA ratios were lower. Amygdaloid HVA/DA ratios declined steadily during pregnancy and were lower postpartum whereas DOPAC/DA ratios did not change. Hippocampal and striatal serotonin (5‑HT) levels were increased postpartum, while the 5‑HT metabolite, 5‑hydroxyindole‑3‑acetic acid (5‑HIAA) was higher at estrous and postpartum than during pregnancy indicating that the state of pregnancy depressed the level of this amine. In In contrast to the hippocampus, no change was measured in hypothalamic 5‑HT metabolism which suggests that these two brain areas are under different regulatory mechanisms. In the frontal cortex, 5‑HIAA levels decreased during pregnancy and remained low postpartum, while 5‑HIAA/5‑HT ratios decreased progressively during pregnancy and postpartum. A negative correlation was observed between the plasma progesterone concentration and striatal DA, HVA, 5‑HT and 5‑HIAA; hypothalamic DA; hippocampal 5‑HT and frontal cortical 5‑HIAA levels which suggests that the increased progesterone levels during pregnancy might have contributed to the reduction in brain DA and 5‑HT concentrations possibly by increasing the rate of metabolism. In addition, there was a strong negative correlation between plasma progesterone concentration and striatal HVA/DA and HVA/DOPAC ratios and amygdaloid HVA/DOPAC ratios. Plasma corticosterone concentrations were positively correlated with hippocampal 5‑HIAA/5‑HT ratios and amygdaloid HVA/DA ratios. Frontal cortical 5‑HT₂ receptor binding decreased at 4 days postpartum relative to estrous values. Occipital cortical 5‑HT₂ receptor binding was significantly increased at 10 and 15 days of pregnancy relative to estrous values. Hypothalamic 5‑HT₂ receptor binding at 20 days of pregnancy was significantly higher than the estrous value, while the DA D₂ receptor value at the same time interval was significantly lower than the estrous value. DA D₂ receptor binding in the amygdala at 4 days postpartum was significantly higher than the estrous level. The estimated K_D (37°C) for [³H]ketanserin in frontal cortical membranes was 0.47 nM with a B_max of 390 fmoles/mg protein. A small, statistically significant decrease was measured in the frontal cortical 5‑HT₂ receptor K_D at 4 days postpartum relative to estrous and 15 day pregnant rat values with no change in the B_max value. Frontal cortical 5‑HT₂ receptor K_D values were positively correlated with striatal HVA concentrations, HVA/DA and HVA/DOPAC ratios. The estimated K_D (37°C) for (±)¹²⁵I‑iodocyanopindolol (¹²⁵ICYP) in hippocampal membranes was 48 pM with a B_max of 53 fmoles/mg protein. The hippocampal β‑adrenoceptor B_max at 4 days postpartum was significantly lower than the 15 day pregnant rat value. A positive correlation was observed between hippocampal β‑adrenoceptor K_D values and plasma progesterone levels. The neurotransmitter changes observed in postpartum rats are accompanied by neurotransmitter receptor changes and may be an underlying factor in the development of postpartum depression (PPD). Doctoral 2012-08-27T12:27:00Z 2012-08-27T12:27:00Z 1991 Thesis http://hdl.handle.net/10019.1/69269 en Stellenbosch University 294 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Hormone receptors Neurotransmitter receptors Hormones Postpartum depression Dissertations -- Medicine Glaser, Jonathan Hormone and neurotransmitter receptor studies in the rat during pregnancy and the postpartum period |
| title | Hormone and neurotransmitter receptor studies in the rat during pregnancy and the postpartum period |
| title_full | Hormone and neurotransmitter receptor studies in the rat during pregnancy and the postpartum period |
| title_fullStr | Hormone and neurotransmitter receptor studies in the rat during pregnancy and the postpartum period |
| title_full_unstemmed | Hormone and neurotransmitter receptor studies in the rat during pregnancy and the postpartum period |
| title_short | Hormone and neurotransmitter receptor studies in the rat during pregnancy and the postpartum period |
| title_sort | hormone and neurotransmitter receptor studies in the rat during pregnancy and the postpartum period |
| topic | Hormone receptors Neurotransmitter receptors Hormones Postpartum depression Dissertations -- Medicine |
| url | http://hdl.handle.net/10019.1/69269 |
| work_keys_str_mv | AT glaserjonathan hormoneandneurotransmitterreceptorstudiesintheratduringpregnancyandthepostpartumperiod |