Luteinizing Hormone-Releasing Hormone Gene Expression in the Bovine Brain: Anatomical Localization and Regulation by Ovarian State1
Autor: | Gary D. Weesner, P.G. Harms, David W. Forrest, J M Wilson, T J Wu, N. H. McArthur, Donald W. Pfaff |
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Rok vydání: | 1993 |
Předmět: |
Estrous cycle
endocrine system medicine.medical_specialty Radioimmunoassay Ovary Cell Biology General Medicine Biology Luteal phase Diagonal band of Broca Preoptic area medicine.anatomical_structure Endocrinology Reproductive Medicine Internal medicine medicine Luteinizing hormone reproductive and urinary physiology hormones hormone substitutes and hormone antagonists Hormone |
Zdroj: | Biology of Reproduction. 49:431-436 |
ISSN: | 1529-7268 0006-3363 |
Popis: | Experiments were conducted to identify neurons in the bovine brain that express the LHRH gene and to determine whether LHRH mRNA levels are influenced by the ovaries. Two groups of postpubertal heifers were utilized: heifers killed during the mid-luteal phase of the estrous cycle (LUTEAL, n = 5) and heifers killed 14-16 wk following ovariectomy (OVX, n = 5). In situ hybridization was performed through use of a 52P-end-labeled deoxyoligonucleotide (59 mer) complementary to the human LHRH mRNA sequence. LHRH-expressing neurons were identified in the diagonal band of Broca, the preoptic area, and the anterior hypothalamus in a manner consistent with immunocytochemical localization. Reduced silver grains, proportional to LHRH mRNA content, were quantified (in pixels, 45x objective) with an image analysis system. Expected serum hormone concentration differences between endocrine states were confirmed by radioimmunoassay for progesterone (LUTEAL > OVX, p LUTEAL, p < 0.01). Compared to the OVX group, LUTEAL heifers had 34% fewer LHRH-expressing neurons (p < 0.05); on the average, these neurons possessed 28% fewer pixels/cell (p < 0.01), indicating fewer copies of LHRH mRNA per cell. When the numbers of pixels in all labeled cells were totalled, LUTEAL animals had 57% fewer pixels (p < 0.05) than did the OVX females-probably reflecting a decrease in LHRH synthetic capacity in the LUTEAL animals. Therefore, during the mid-luteal phase of the bovine estrous cycle, ovarian steroid (i.e., luteal progesterone) suppression of LHRH release (as reflected by serum LH) is coincident with decreased LHRH mRNA in the brain. In summary, the quantity of LHRH mRNA, as well as the number of detectable LHRH-expressing neurons in the bovine brain, is influenced by the ovaries. |
Databáze: | OpenAIRE |
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