Gamma-aminobutyric acid as a regulator of luteinizing hormone-releasing hormone release from the hypothalamus /
| Main Author: | |
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1989.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy |
| Abstract: | Luteinizing Hormone Releasing Hormone (LHRH) is released from the hypothalamus and is regulated by neurotransmitters located in the preoptic area and hypothalamus, γ-aminobutyric Acid (GABA) is located in the hypothalamus thus it has the potential for regulating LHRH release. Hypothalamic tissue from: 1) adult male, 2) ovariectomized (OVX), and 3) prepubertal female rats was incubated in 12 x 75 mm polypropylene culture tubes containing 0.6 ml of Krebs-Ringer bicarbonate (plus 10 mM glucose, 0.1% bovine serum album in and 0.06 g/1 bacitracin) for 2 hours at 37°C under an atmosphere of 95% O2 and 5% CO2 . At 30, 60, 90 and 120 min 0.5 ml of incubate was removed from each tube (samples 1-4 respectively) and replaced with fresh media. LHRH (pg/30 m in) in the 0.5 ml incubate was determined by radioimmunoassay. Values expressed are the difference between samples 2 (control) and 3 (treated; 3-2; mean difference). All treatments occurred during the 3rd period. Generally, untreated tissues released less LHRH in the 3rd sample than the 2nd resulting in negative mean difference values. The medial basal hypothalamus (MBH) from OVX rats when exposed to 60 mM KC1, in equimolar substitution for NaCl, released elevated concentrations of LHRH into the culture medium (-3.1±0.5/64; mean difference [pg/30 min]±SEM /n; 4.8±1.4/9; control vs KC1 treated respectively; p<0.05) demonstrating the validity of the incubation procedure. Hypothalamic tissues were treated during the 3rd period (60-90 min) with GABA or its analogues. Male rat MBH, with the infundibulum (INF) attached, released greater concentrations of LHRH compared to control (C, -1.6±1.5/11) when treated with 0.1 mM (5.9±2.5/12; p<.05) but not 1.0 mM (1.9±1.1/11) GABA. In contrast, LHRH release from OVX rat hypothalamic tissues was not different from control; thus, did not respond to GABA or its analogues... |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Physiology of Reproduction." |
| Physical Description: | x, 81 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |