Annexin 5 messenger ribonucleic acid expression in pituitary gonadotropes is induced by gonadotropin-releasing hormone (GnRH) and modulates GnRH stimulation of gonadotropin release
| Autor: | Mina Sakai, Seishi Etoh, Mayumi Nishida, Shiro Kurusu, Inoru Hashimoto, Mitsumori Kawaminami, Hiroko Miyaoka |
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| Rok vydání: | 2002 |
| Předmět: |
endocrine system
medicine.medical_specialty medicine.drug_class Endocrinology Diabetes and Metabolism Ovariectomy Gene Expression Gonadotropin-releasing hormone In Vitro Techniques Gonadotropic cell Oligodeoxyribonucleotides Antisense Gonadotropin-Releasing Hormone Cellular and Molecular Neuroscience Endocrinology Anterior pituitary Annexin Internal medicine medicine Animals RNA Messenger Annexin A5 Cycloheximide Rats Wistar Cells Cultured Protein Synthesis Inhibitors Endocrine and Autonomic Systems Chemistry Luteinizing Hormone Gonadotropin secretion Rats medicine.anatomical_structure Pituitary Gland Female Gonadotropin Follicle Stimulating Hormone Luteinizing hormone Gonadotropins Hormone |
| Zdroj: | Neuroendocrinology. 75(1) |
| ISSN: | 0028-3835 |
| Popis: | Our previous studies on annexin 5, a member of the annexin family of proteins, have shown its expression in the anterior pituitary gland, its preferential distribution in gonadotropes, and its increase after ovariectomy. In the present study, we examined (1) whether annexin 5 is synthesized in gonadotropes, (2) whether its expression is under the control of gonadotropin-releasing hormone (GnRH), and (3) the effect of annexin 5 on gonadotropin release. Large cells, also called castration cells, appeared in anterior pituitary tissue 3 weeks after ovariectomy. These cells have been confirmed to be hyperfunctioning gonadotropes and are easily discriminated from other pituitary cells without immunostaining. Using in situ hybridization with a digoxigenin-labeled ribonucleic acid probe, enhanced expression of annexin 5 messenger ribonucleic acid (mRNA) in these gonadotropes was clearly demonstrated. Northern blot analysis showed an increase in the level of annexin 5 mRNA expression 3 weeks after ovariectomy. It was lessened 3 h after the injection of Cetrorelix (GnRH antagonist, 10 microg i.v.). Administration of a GnRH analog [GnRHa; Des-Gly 10 (Pro9) GnRH ethylamide, 0.2 ml of 2.5 microg/ml saline ten times intraperitoneally at 30-min intervals] significantly increased pituitary annexin 5 mRNA. In primary cultures of anterior pituitary cells, recombinant rat annexin 5 stimulated luteinizing hormone (LH) and follicle-stimulating hormone (FSH) release in a dose-dependent manner. Concomitant administration of annexin 5 (1 microg/ml) and GnRHa augmented the LH and FSH release induced by GnRHa. After a 1-hour incubation, cycloheximide (10 microg/ml) apparently inhibited the LH response to GnRHa, while annexin 5 (2 microg/ml) moderated this inhibition. Further, the antisense oligodeoxynucleotide to annexin 5 mRNA blunted the LH response to GnRHa. It is thus concluded that annexin 5 is synthesized in the gonadotropes under the effect of GnRH, and it is suggested that annexin 5 synthesis mediates at least partly GnRH receptor signaling to stimulate gonadotropin secretion. |
| Databáze: | OpenAIRE |
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