Stimulation of gonadotrophs by pituitary portal vessel infusion of superactive LH-RH analogues: an ultrastructural study
| Autor: | S.J. Poliakoff, R.M.G. Nair, J.L. Luborsky-Moore, W.C. Worthington |
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| Rok vydání: | 1978 |
| Předmět: |
Male
endocrine system medicine.medical_specialty Endocrinology Diabetes and Metabolism Golgi Apparatus Stimulation Gonadotropin-releasing hormone Biology Gonadotropic cell Exocytosis Gonadotropin-Releasing Hormone Cellular and Molecular Neuroscience symbols.namesake Endocrinology Pituitary Gland Anterior Internal medicine medicine Animals Endocrine and Autonomic Systems Portal Vein Endoplasmic reticulum Cell Membrane Radioimmunoassay Golgi apparatus Luteinizing Hormone Gonadotropin secretion Rats Pituitary Gland Gonadotropins Pituitary symbols Subcellular Fractions |
| Zdroj: | Neuroendocrinology. 26(2) |
| ISSN: | 0028-3835 |
| Popis: | LH-RH or its superactive analogues were infused into pituitary portal vessels of adult male rats for 1 min; pituitaries were then fixed for routine electron microscopy 1 min, 30 min and 3 h after infusion. A maximal increase of granule release at 2 min, and a maximal increase in synthetic activity (i.e., dilated cisternae of rough endoplasmic reticulum (RER) and Golgi apparatus (GA)) at 30 min, occurred in gonadotrophs in response to both LH-RH and the superactive analogues, but not to saline infusion. Only gonadotrophs from analogue infused pituitaries showed a high level of exocytosis and protein synthesis at 3 h. In addition, the superactive analogues typically stimulated formation of large vacuoles of RER at 30 min and 3 h that resembled those seen in ‘signet ring’ cells following castration. Radioimmunoassay (RIA) values of serum LH supported these observations. The results of this study provide morphological evidence for a prolonged action of the superactive analogues of LH-RH on both gonadotropin secretion and synthesis under physiological conditions. |
| Databáze: | OpenAIRE |
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