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  • 1
    Electronic Resource
    Electronic Resource
    The fine structure of the lutein cells in the blue fox (Alopex lagopus) with special reference to the secretory activity during pregnancy (1974)
    Springer
    Cell & tissue research 149 (1974), S. 61-79 
    Details
    ISSN: 1432-0878
    Keywords: Ovary ; Blue fox ; Lutein cells ; Plasma progesterone ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An electron microscopic investigation of the lutein cells of the blue fox was undertaken, based on the hypothesis that differences in plasma progesterone levels at differing stages of pregnancy might be reflected in the ultrastructural organization. Comparisons were made between corpora lutea taken from animals mated 1, 2, 5, 14, 18, 20, 28, 33, 36, 39 and 45 days after the estimated time of ovulation. Measurements of progesterone on plasma samples were performed by a rapid competitive protein-binding assay. During the period with increasing and/or high plasma progesterone levels, (i.e. 1 to 14 days after ovulation) the lutein cells are characterized by evenly distributed cisternal agranular ER, mitochondria with both tubular and lamellar cristae, and electron-dense lipid droplets. The abundant agranular ER is closely associated with the lipid droplets and mitochondria. During the period with declining plasma progesterone levels, the lutein cells present a different morphological picture: the agranular ER assumes the form of bundles of parallel tubules disposed in several planes. During the latest stages observed, these “bundles” are disrupted and most of the agranular ER become arranged in smaller concentric whorls. Both kinds of whorls regularly enclose lipid droplets, dense bodies and mitochondria. The regions between the whorls contain scattered cisternae of endoplasmic reticulum, ribosomes, mitochondria and lysosome-like dense bodies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209050
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The fine structure of the lutein cells in the mink (Mustela vison) with special reference to the secretory activity during pregnancy (1973)
    Springer
    Cell & tissue research 138 (1973), S. 523-544 
    Details
    ISSN: 1432-0878
    Keywords: Ovary ; Mink ; Lutein cells ; Plasma progesterone ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the lutein cells in the mink throughout pregnancy and the regression periodpost partum is described. To correlate the fine structure with the changes in the peripheral plasma progesterone levels, the concentrations of progesterone were measured by a rapid competitive protein-binding assay. Even during the delay period (e.g. as long the plasma progesterone levels remain at the basal level, 〈8ng/ml), the lutein cells in the mink exhibit structural criteria of functional activity. However, the increase in progesterone secretion is accompanied by some morphological transformations, characterized by the presence of more and more small dense homogenous bodies in the cytoplasm, which become irregular and scalloped during the stage with maximum release of progesterone. At this stage the agranular endoplasmic reticulum is often cisternal or vesicular. During the decline of the progesterone levels, typical and moderate electron-dense lipid droplets are found increasingly more within the lutein cells. The expanded agranular ER is now more sparse, while the granular ER becomes more pronounced, often forming parallel arrays. During this phase the mitochondria become elongated, dumb-bell, or cup shaped. After parturition the corpora lutea consist of cells in various stages of degeneration. At day 14post partum only a few lutein cells are still identifiable. Evidently the observed morphological changes take place in the lutein cells during the life span of corpora lutea. This feature lends further support to the concept that the mink lutein cells are steroid-producing cells and furthermore, that the corpora lutea may be the main sites of gestagen production during pregnancy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00572294
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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