Elektronenmikroskopische Untersuchungen der hyperplastischen Langerhans'schen Inseln der Stachelmaus (Acomys cahirinus) vor und w�hrend der Entwicklung eines diabetischen Syndroms

Pictet, Raymond; Orci, Lelio; Gonet, A; Rouiller, C; Renold, Albert E.

doi:10.1007/bf01222197

Cited by 96 publications

(44 citation statements)

References 23 publications

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“…If we assume that the intracellular leucine pools were similar in the two species, then proinsulin synthesis would be similar but total protein synthesis five times greater in acomys than the rat. The latter would be in accord with previous morphological evidence from acomys islets [1][2][3]. In the latter studies it was concluded that acomys islets contained many polyribosomes, a highly structured and well developed endoplasmic reticulum and prominent Golgi complexes all of which are indicative of very active protein synthesis [20].…”

Section: Discussionsupporting

confidence: 87%

“…The results demonstrate a decreased responsiveness of proinsulin synthesis to glucose in acomys and are discussed in terms of the known decreased sensitivity of insulin release in this animal. Acomys cahirinus maintained in the Geneva colony exhibit hyperplasia of the islets of Langerhans [1][2][3] and a retarded as well as reduced rate of insulin release in response to glucose challenge by comparison with rats or mice [4][5][6][7]. These differences in the response profile to glucose have been detected in vivo, after either intraperitoneal [4][5] or intravenous [6] glucose injection, and in vitro, using isolated islets [7][8][9].…”

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confidence: 99%

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Proinsulin synthesis in islets of Langerhans from spiny mice (Acomys cahirinus). comparison with rats and mice

et al. 1976

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Summary. Proinsulin synthesis in response tO different concentrations of glucose has been studied in islets of Langerhans of acomys, rat and mouse. The response to increased glucose was small in acomys when compared with rat or mouse. The time course of the effect of glucose on proinsulin synthesis was also studied in sequential 15 min periods up to 60 min. With 5.5 mM glucose the rate of 3H-leucine incorporation for acomys islets was greater over the periods 15-30, 30-45 and 45-60 min after the addition of glucose to the islets than at 0-15 rain. By contrast rat islets exhibited a greater glucose-induced stimulation between 15-30 and 30-45 min relative to the 0-15 min period and a further increase of the incorporation rate between 45 and 60 min. With 27.5 mM glucose acceleration of incorporation relative to the first 15 min period occurred at 15-30 min; it was then stable up to 60 min for islets both from acomys and from rat. Incorporation into total protein was much greater in acomys than in rat or mouse: thus in 2.75 mM glucose, acomys islets incorporated 5 and 19 times more 3H-leucine into total protein than did islets from rat or mouse respectively. In 27.5 mM glucose the incorporation into total protein of the islets from acomys was 4 and 13 times greater. Islet content of insulin was similar for all three species. No significant changes in ATP content were observed in response to changes in glucose concentration from 2.75 to 27.5 mM. The results demonstrate a decreased responsiveness of proinsulin synthesis to glucose in acomys and are discussed in terms of the known decreased sensitivity of insulin release in this animal. Acomys cahirinus maintained in the Geneva colony exhibit hyperplasia of the islets of Langerhans [1][2][3] and a retarded as well as reduced rate of insulin release in response to glucose challenge by comparison with rats or mice [4][5][6][7]. These differences in the response profile to glucose have been detected in vivo, after either intraperitoneal [4][5] or intravenous [6] glucose injection, and in vitro, using isolated islets [7][8][9]. While acomys islets respond slowly to glucose, the total release of insulin over a two hour period may be comparable to that of rats, at least at higher glucose concentrations [7][8][9], suggesting predominantly early decreased sensitivity to glucose. Indeed, when the early and late release phases were compared in some detail [7][8][9], it was confirmed that the early phase (1-10 rain) of insulin release from acomys islets exhibited both decreased sensitivity to glucose and a decreased release capacity. By contrast, the late phase (20-30 rain) of insulin release from acomys islets exhibited only decreased sensitivity to glucose. As these time/secretion characteristics resemble in some respects observations reported in latent diabetes as well as maturity onset diabetes in man [10][11][12] acomys has attracted attention as a possible "model" of potential usefulness. Because of this and because the insensitivity to glucose might be carried over to the ...

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Section: Discussionsupporting

confidence: 87%

mentioning

confidence: 99%

Proinsulin synthesis in islets of Langerhans from spiny mice (Acomys cahirinus). comparison with rats and mice

et al. 1976

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“…The identification is made possible by the specific staining characteristics of B cells [9,10] as well as the alterations seen either in spontaneous diabetes [20,23,30] or after the administration of agents such as alloxan [4] or streptozotocin [14], which lead to diabetes, and to the disappearance of both B cells and insulin from the pancreas.…”

Section: Discussionmentioning

confidence: 99%

“…17, Fig. 18) than is true for the TSH-produeing cell granules which, furthermore, are very much smaller [30,38,42].…”

Section: Diabetqlogiamentioning

confidence: 98%

Structural evidence for glucagon producing cells in the intestinal mucosa of the rat

et al. 1968

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Summary. The gastro-intestinal mucosa of the rat has been systematically studied with the electron-microscope at the following levels : gastric fundus, pylorus, duodenum, jejunum and ileum. Two types of non-digestive epithelial cells have been observed, both exhibiting electron-dense granulations, both candidates for endocrine activity. The first type of cells contains round granules bearing remarkable similarity to the granules of pancreatic endocrine A cells. The second cell type is characterised by strikingly polymorphic granulations and would appear to correspond to the so-called enterochromaffine cells of light-microscopy. On the basis of this morphological criterion, and of the biochemical evidence suggesting the existence of a substance in the intestine which greatly resembles glucagon, biologically and immunologicMly, it is proposed that this substance is secreted by the first type of cells which resemble the pancreatic A cells. Mise en dvidence par la microscopic dIeetronique de cellules d glucagon dans la muqueuse digestive du ratRdsum& L'Stude au microscope 61ectronique de Fintestin de rat ~ diffdrenbs niveaux: estomac, duod4num, j4junum et il4on, permet d'observer 2 types de cellules granulations denses. Le premier type, dent les granulations sent rondes, est semblable aux cellules A du paner4as. Le deuxigme type de cellules, dent les granulations sent polymorphes, est associ4 aux eellules dites ent4ro-chromaffines. Sur la base de ce eribgre morphologique, et des dorm4es biochimiques affirmant l'existence dans l'intestin d'une substance biologiquement et immunologiquement proche du glucagon, il est propos6 de situer la synthgse ct sgcr4tion du glueagon intestinal au niveau de ees cellules endocrines intestinales de type A. Ele/ctronenmilcrostcopische Darstellung von Glucagon-produzierenden Zellen im GastrointestinaltralctZusammenfassung. Bei einer systematischen Untersuch~mg der Magen-Darm-Schleimhaut mit Hilfe des Elektronenmikroskopes wurden zwei Arten yon besonderen Zellen in deren Epithelien festgestellt, die m6gliche Trager endokriner T/~tigkcit sind. Beide sind durch elektronenoptisch dunkle Granula gekennzeichnet. Der erste Typ enth/ilt runde Einschliisse, die den Sekret-Granula der endokrinen A-Zellen des Pankreas sehr ~hnlich sind. Der zweite Zelltyp weist auffallend polymorphe Sekretgranula auf, die derjenigen der sogenannten enterochromaffinen Zellen ira Lichtmikroskop entsprechen diirften. Diese morphologische Eigenschaft sowie die biochemischen Beobaehtungen, welche auf das Vorhandensein einer dem Gincagon biologisch und immunologisch/~hnlichen Substanz im ])arm deuten, lassen die Annahme zu, dal3 die den pankreatischen A-Zellen ~lmlichen Zellen fiir die Sekretion des Darm-Glucagons verantwortlich sind.

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“…Within each islet, approximately 80% of the cells were beta-cells but, contrary to the appearances in the sand rat [11] and the spiny mouse [12] where alpha-cells are peripherally sited, in the tuco-tuco they were centrally arranged in common with a variety of hot-climate rodents [13]. Marked islet cell hyperplasia was seen in some glands (Fig.…”

Section: Histological Observations 1 Pancreasmentioning

confidence: 92%

The diabetic syndrome in the tuco-tuco (Ctenomys talarum)

Wise

Weir²,

Hime

et al. 1972

Diabetologia

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Summary. A syndrome of diabetes, which appears to be dependent upon diet, is described in an Argentine rodent, the tuco-tuco. Hyperglycaemia and cataract are shown to be inversely related to age and associated with excess mortality. Pancreatic islet, renal glomerular and lens changes are similar to those of human diabetics. It is suggested that this species forms a useful model of h u m a n maturity onset diabetes. Le syndrome diabdtique chez le Tuco-tuco (Ctenomys talarum)Rdsumd. Les

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Elektronenmikroskopische Untersuchungen der hyperplastischen Langerhans'schen Inseln der Stachelmaus (Acomys cahirinus) vor und w�hrend der Entwicklung eines diabetischen Syndroms

Cited by 96 publications

References 23 publications

Proinsulin synthesis in islets of Langerhans from spiny mice (Acomys cahirinus). comparison with rats and mice

Proinsulin synthesis in islets of Langerhans from spiny mice (Acomys cahirinus). comparison with rats and mice

Structural evidence for glucagon producing cells in the intestinal mucosa of the rat

The diabetic syndrome in the tuco-tuco (Ctenomys talarum)

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