Zur Histologie und Cytologie der Kropfmilchbildung der Taube

Weber, Wim

doi:10.1007/bf00325118

Cited by 17 publications

(14 citation statements)

References 16 publications

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“…Thus, we suggest that the lining epithelia of the three regions studied are capable to form and/or accumulate lipid within their cells, although in much more quantity at the lateral lobes. This is in disagreement with Weber's [1962] andForssmann s [1965] find ings who state that these lipid droplets are exclusive of the 'glandular-portion and absent at the median portion of the crop.…”

Section: Pigeons In Resting 'Milk Gland' (Control Group)contrasting

confidence: 55%

“…Lipid droplets in the lateral lobes of resting crop have been reported also by other workers, e.g. Valle [1942], Weber [1962], Dumont [1965], Forssmann [1965] and Morato-Manaro et al [1965]. On the other hand, lipid droplets should not be considered restricted to the lateral lobes, since they were also found at the two other regions studied.…”

Section: Pigeons In Resting 'Milk Gland' (Control Group)mentioning

confidence: 54%

“…On the other hand, the lateral portions of this region responded more quickly to prolactin. Forssmann [1965] also reports the presence of some lipid droplets at the median portion of the crop of treated ani mals, while Weber [1962] assumes that the median region of treated animals behaved like that of inactive pigeons, although at the region adjacent to the lateral lobes the lipid forma tion is more intense.…”

Section: Pigeon With Active 'Milk Gland' ( Which Re Ceived Injectionsmentioning

confidence: 99%

“…When the epi thelial cells are laden with lipid, they are exfoliated into the lumen of the crop, being furnished as 'milk' to the young. The increase (in size) of the droplets may result from the coalescence of the smaller ones [Weber, 1962;Dumont, 1965;Moratd-Manaro et al, 1965] as well as from the synthesis of lipid [Dumont, 1965;Forssmann, 1965], Nicoll [1969 sug gested that the change in the histological aspect of cells of the mucosal epithelium after stimu lation may reflect an aggregation of intracel lular lipid into granules rather than the uptake or synthesis of fat by the cells. Chadwick and Jordan [1971] have shown that there was no difference in lipid concentration whether or not the crop epithelium contained sudanophil lipid droplets (treated with prolactin or paralactin, a prolactin-like fish hormone [Ball, 1965]).…”

Section: Pigeon With Active 'Milk Gland' ( Which Re Ceived Injectionsmentioning

confidence: 99%

“…The study of the crop-stimulating effect of pro lactin is of a great practical importance, since it still represents the basis for the most reliable methods for assaying this hormone [Apostolakis, 1968], One of the most striking characteristics of the epithelium of the pigeon crop "glands' after stimulation of the crop by prolactin, either by the natural stimulus of incubating the eggs or by injection, is the accumulation of intra cellular lipid [Chadwick and Jordan, 1971], The present work was designed to examine the effect of prolactin on lipid droplets not only of the lining epithelium of the lateral lobes (crop "gland", 'milk gland"), but also of other regions of the organ like the median region near the cervical esophagus and median region near the thoracic esophagus, since only few authors [Weber, 1962;Forssmann, 1965] have studied the presence of lipid in other regions but the lateral lobes. Thus, we decided to examine the pres ence of lipid in the lining epithelium of those three regions of the crop, during the rest and activity of the "milk gland' (in physiologic incubation or under the action of exogenous prolactin).…”

Section: Introductionmentioning

confidence: 99%

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Lipid droplets in the lining epithelium of the crop of <i>Columba livia</i>

Lima¹

1978

Cells Tissues Organs

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Presence and distribution of lipid were studied in the lining epithelia of three regions of the pigeon (Columba livia) crop: lateral lobes, median region near the cervical esophagus and median region near the thoracic esophagus. During the resting phase of the ‘milk gland’, insulated lipid droplets were observed within the lining epithelium of the three regions studied. On the other hand, during the activity of the ‘milk gland’ (under action of exogenous prolactin and in natural incubation), only the lateral lobes showed a remarkable increase in the amount of lipid, whereas both median regions showed only an inexpressive increase of lipid within their epithelium.

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Section: Pigeons In Resting 'Milk Gland' (Control Group)contrasting

confidence: 55%

Section: Pigeons In Resting 'Milk Gland' (Control Group)mentioning

confidence: 54%

Section: Pigeon With Active 'Milk Gland' ( Which Re Ceived Injectionsmentioning

confidence: 99%

Section: Pigeon With Active 'Milk Gland' ( Which Re Ceived Injectionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Lipid droplets in the lining epithelium of the crop of <i>Columba livia</i>

Lima¹

1978

Cells Tissues Organs

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Pigeon crop-sac as a model system for studying the direct and indirect effects of hormones and growth factors on cell growth and differentiation in vivo

Nicoll

1990

J. Exp. Zool.

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The pigeon crop-sac is a n underappreciated and underutilized model that can be used to study the direct and indirect effects of hormones, growth factors, and other agents on cell proliferation and differentiative processes in vivo. It can thus allow the uncertainties that attend many in vitro methods to be avoided. In addition, the crop mucosal cells are homogeneous and the organ is structurally much less complex than most other hormone-responsive target organs, such as the mammary gland or prostate. The organ is well suited for various other studies such as analysis of second-messenger systems for PRL and growth factors and the effects of growth-inhibitory substances.The most widely used procedures for testing the direct effects of hormones and growth factors on cell metabolism and/or proliferation involve in vitro methods with primary culture or established cell lines. Other in vitro studies apply similar analyses to tissue slices or fragments. Although these techniques yield useful information about actions of and interactions between or among hormones and growth factors on various cell functions, concern exists about the physiological significance of some results from such studies because the in vitro environment does not duplicate conditions found in vivo.The pigeon crop-sac is a unique structure because it allows the direct effects of hormones and growth factors on proliferation and the differentiated functions of a specialized cell type to be studied in vivo. The crop is found in all birds and in many species it is used as a temporary storage site for food. In some species it is also used as a display organ during courtship. In pigeons and doves, the crop-sac is further specialized to carry out an additional function-the nourishment of their young (Bernard, 1859; Beams and Meyer, which is used to feed the young squabs or nestlings. In 1935, W.R. Lyons discovered that if PRL was injected intradermally over the crop-sac, it caused local proliferation of mucosal cells under the site of injection (Lyons and Page, '35). Because of the bi-lobed nature of this structure (Fig. 1) it is possible to compare the activities of two different preparations in the same birds by injecting them over each lobe of the crop. It is also possible to test interactions between or among hormones or growth factors that are applied directly to the tissues or by injection of one preparation over the crop while a second substance is administered at a distant site so that it has systemic actions. Thus, the crop-sac allows for various kinds of analysis in vivo that could not be duplicated in vitro. Various injection schedules and procedures of response quantification have been used in studying the direct actions of PRL on the crop-sac (see Hiroi, '71; Nicoll, '73). METHODSThe procedure which we routinely use involves removing the feathers that overlie the crop of the pigeons on the day prior to the beginning of the series of four local injections. After the first intracutaneous injection is given the injection site is marked so...

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Zum Problem der Amitose

Bucher¹

1971

Der Zellkern I

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Zur Histologie und Cytologie der Kropfmilchbildung der Taube

Cited by 17 publications

References 16 publications

Lipid droplets in the lining epithelium of the crop of <i>Columba livia</i>

Lipid droplets in the lining epithelium of the crop of <i>Columba livia</i>

Pigeon crop-sac as a model system for studying the direct and indirect effects of hormones and growth factors on cell growth and differentiation in vivo

Zum Problem der Amitose

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