Glucagon-like peptide-1 control of GnRH secretion in female sheep
| Autor: | Belinda A. Henry, Iain J. Clarke, Leila Arbabi, Qun Li |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
0301 basic medicine
endocrine system medicine.medical_specialty Endocrinology Diabetes and Metabolism 030209 endocrinology & metabolism Gonadotropin-releasing hormone Luteal phase Glucagon-Like Peptide-1 Receptor Gonadotropin-Releasing Hormone 03 medical and health sciences 0302 clinical medicine Endocrinology Kisspeptin Glucagon-Like Peptide 1 Internal medicine medicine Animals Receptor Microinjection Estrous cycle Sheep Chemistry Median Eminence 030104 developmental biology Hypothalamus Median eminence Exenatide Female hormones hormone substitutes and hormone antagonists |
| Zdroj: | Journal of Endocrinology. 248:325-335 |
| ISSN: | 1479-6805 0022-0795 |
| Popis: | The role of glucagon-like peptide-1 (GLP-1) on gonadotropin-releasing hormone (GnRH) secretion was investigated in ovariectomised (OVX) ewes, in which GnRH and luteinising hormone (LH) secretion had been restrained by treatment with oestrogen and progesterone. Guide tubes for microinjection were placed above the median eminence (ME) and the animals were allowed to recover for 1 month. Jugular venous blood samples were taken via cannulae at 10 min intervals. Vehicle (50 nL) was injected into the ME at 2 h, followed by injection of GLP-1 ((7-36)-amide – 0.5 or 1 nmol) or its receptor agonist, exendin-4 (0.5 nmol) at 4 h (n = 5). Plasma LH levels were quantified as a surrogate measure of GnRH secretion. GLP-1 microinjection into the ME elicited a large amplitude LH pulse in jugular plasma, the effect was greater at the higher dose. Exendin-4 microinjection caused a large, sustained increase in plasma LH levels. To determine how GLP-1 might exert an effect on GnRH secretion, we employed double labelled in situ hybridisation, with RNAScope, for co-localisation of the GLP-1 receptor (GLP-1R) in GnRH, Kisspeptin and NPY cells in the hypothalami of three ewes in the luteal phase of the estrous cycle. GLP1R expression was clearly visible but the receptor was not expressed in GNRH1 or NPY expressing neurons and was visualised in KISS1 expressing neurons. We conclude that GLP-1 may act at the level of the secretory terminals of GnRH neurons in the ME to stimulate GnRH secretion, the pathway through which such effect is manifested remains unknown. |
| Databáze: | OpenAIRE |
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