To investigate the role of the mediobasal hypothalamus (MBH) in diabetic gonadal axis disorders, the MBHs of adult male streptozocin-induced diabetic (STZ-D) rats were examined after incubation in basal conditions or in K+-enriched medium and compared with those of controls. Diabetes lasted 1 mo. Both luteinizing-hormone-releasing hormone (LHRH) release and MBH morphology were studied. After incubation in basal conditions, the LHRH release was unchanged. By light microscopy, the dilated-axon cross sections were more numerous (P < .01) in the basal arcuate nucleus and in the median eminence. By electron microscopy, the ratio of exocytoses to neurosecretory granules observed in the median eminence axon cross sections was smaller (P < .05). The total LHRH immunoreactivity, the number of labeled axons, and the amount of positive material in the axons were reduced (P < .05). After incubation in K+-enriched medium, the LHRH release was markedly reduced (P < .01). The number and area of dilated-axon cross sections, possibly because of the relation between exocytosis and physiological dilation, were less augmented (P < .01). Whereas the number of exocytoses and the ratio of exocytoses to neurosecretory granules were not decreased, the total LHRH immunoreactivity and the number of labeled axons were reduced (P < .05). The releasable LHRH pool therefore seems to be exhausted in control MBH because of long-term stimulation and reduced in the MBH of STZ-D rats because of diabetes. In conclusion, STZ-D causes functional and anatomical MBH lesions that should be pathogenetically relevant for the disorders of the gonadal axis documented in this animal model.
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Original Articles|
April 01 1989
Functional and Morphological Changes in Mediobasal Hypothalamus of Streptozocin-induced Diabetic Rats: In Vitro Study of LHRH Release
Gilberto E Bestetti;
Gilberto E Bestetti
Division of Experimental Pathology, Institute of Animal Pathology, University of Berne
Bern
Division of Endocrinology, Department of Internal Medicine, University Hospital
Lausanne, Switzerland
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Claude E Boujon;
Claude E Boujon
Division of Experimental Pathology, Institute of Animal Pathology, University of Berne
Bern
Division of Endocrinology, Department of Internal Medicine, University Hospital
Lausanne, Switzerland
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Marianne J Reymond;
Marianne J Reymond
Division of Experimental Pathology, Institute of Animal Pathology, University of Berne
Bern
Division of Endocrinology, Department of Internal Medicine, University Hospital
Lausanne, Switzerland
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Giovanni L Rossi
Giovanni L Rossi
Division of Experimental Pathology, Institute of Animal Pathology, University of Berne
Bern
Division of Endocrinology, Department of Internal Medicine, University Hospital
Lausanne, Switzerland
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Address correspondence and reprint requests to Prof. Dr. G.L. Rossi, Division of Experimental Pathology, Institute of Animal Pathology, University of Berne, P.O. Box 2735, CH-3001 Bern, Switzerland.
Diabetes 1989;38(4):471–476
Article history
Received:
May 04 1988
Revision Received:
October 13 1988
Accepted:
October 13 1988
PubMed:
2647554
Citation
Gilberto E Bestetti, Claude E Boujon, Marianne J Reymond, Giovanni L Rossi; Functional and Morphological Changes in Mediobasal Hypothalamus of Streptozocin-induced Diabetic Rats: In Vitro Study of LHRH Release. Diabetes 1 April 1989; 38 (4): 471–476. https://doi.org/10.2337/diab.38.4.471
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