Testosterone metabolism in the uropygial gland of the quail

The metabolism of testosterone in the uropygial gland of the quail principally results in the production of 17 alpha, 5 beta derivatives. Moreover, an unusually small amount of testosterone is converted to 5 alpha-dihydrotestosterone. These results question the role played by intracellular 5 alpha-reduction in the response of the gland to testosterone stimulation.     

Epidermal growth factor inhibits morphogenesis of the embryonic quail uropygial gland cultured in vitro

Formation of the uropygial papilla and glandular lumena was inhibited when the uropygial rudiment of a day 8 1/3 quail embryo was cultured for 2 days in a chemically defined medium in the presence of 50 ng/mL of epidermal growth factor (EGF). The epithelium of EGF-treated explants remained at the placode stage, or underwent minor invagination into the mesenchyme and became stratified like that of a 12- or 13-day-old embryo. EGF promoted cellular proliferation in the uropygial epithelium and the epidermis adjacent to the gland and it shortened the lag phase of proliferation and markedly stimulated epithelial DNA synthesis, detected immunocytochemically by labeling explants with 5-bromodeoxyuridine (BrdU). The maximal labeling index in EGF-treated uropygial epithelium was 55% higher than in the control. Electron microscopic observation revealed that the basal lamina had become irregular in the EGF-treated explants and that epithelial cytoplasmic processes penetrated through the basal lamina toward the mesenchyme. These same phenomena are observed in vivo when the glandular buds are formed during day 12–13. Some precocious changes occurred in the uropygial epithelium when the rudiment was cultured in the presence of EGF.     

Absence of 5 alpha-dihydrotestosterone action in the sebaceous-like uropygial gland of the male Japanese quail

The uropygial gland of the quail, a sebaceous-like gland, has been proven to be androgen-dependent. Waxes secreted by this gland consist of fatty acids esterified by alkane-2,3-diols [12]. In castrated quails, the relative concentration of dodecane diol was enhanced after testosterone treatment; but 5 alpha-DHT could not evoke any increase in the relative concentration of dodecane diol. It is not possible from our present results to know if this lack of gland response to DHT administration is related to a high level of DHT metabolism in the gland cells or to a decreased affinity of the androgen receptor for DHT. However, because of the high similarity existing between uropygial gland of birds and mammalian sebaceous glands, these results give rise to the question of the true role of DHT in mammalian sebaceous glands.     

Ultrastructural changes in the uropygial gland of the male Japanese quail,Coturnix coturnix,after testosterone treatment

Summary The ultrastructure of the uropygial gland of the male quail was compared to that of the sebaceous gland of the male rat after castration and testosterone treatment of both species. In intact animals, the differentiating cells of these glands displayed almost the same pattern as regards their smooth endoplasmic reticulum, an organelle involved in lipogenesis in both cases. Castration reduced the volume of this organelle, while testosterone administration restored cell morphology to a normal or supranormal level. Finally, this study showed that at ultrastructural level, there is a close functional analogy between the uropygial gland of quail and the sebaceous glands of rats as regards their androgen dependency. Consequently, the uropygial gland might be an attractive model for study of action of androgens on sebaceous-like glands.     

Cytological differentiation in the uropygial gland.

Ultrastructural changes were studied in the cells undergoing secretory differentiation in zone I of the tubules of the uropygial gland of White Plymouth Rock chickens. A layer of basal cells and four secretory stages are recognized as the cells migrate from the periphery to the lumen of tubules and progressively elaborate a secretion product. Basal cells, containing rough endoplasmic reticulum and free ribosomes, rest on the basement membrane and are the source from which secretory cells arise. Dilated perinuclear cisternae and the proliferation of smooth endoplasmic reticulum in the form of vesicles, invaginated sacs and cusp-shaped cisternae indicate the onset of lipgenesis in stage I cells. The perinuclear cisternae are more dilated and the endoplasmic reticulum is composed on saccules and cisternae in stage II cells. Stage III cells are characterized by concentric lamellae of endoplasmic reticulum surrounding secretory droplets. Dilated cisternae of endoplasmic reticulum and secretory droplets both contain a reticular substance. The perinuclear cisternae of stage III cells have returned to normal dimensions. Large mature lucent secretory droplets, lined with electron-dense material, fill the cytoplasm ostage IV cells which degenerate and release their secretory product into the tubule lumen. Spherical membrane-bound compartments containing a mottled substance of moderate electron density occur in basal cells and all subsequent secretory stages. These mottled bodies are surrounded by saccules of endoplasmic reticulum in stage II cells and are intimately associated with secretory droplets in stage III cells, but there is no evidence that they give rise to secretory droplets and their role in secretory differentiation is unknown.     

Action of estriol on the uropygial gland activity in pigeon

Administration of estriol (Sigma Chemical Co., U.S.A.) in the female young-adult pigeons at a dose of 50 micrograms/bird/day for 7 consecutive days caused atrophy of the uropygial gland, associated with increased cytopycnosis and drastic cell loss within the holocrine alveoli and reduction in the content of the glandular lipids. Probable mode of action of this steroid upon the uropygial gland has been suggested in the light of the recent data on its anti-estradiol property manifested in rat uterus.     

Recessive inherited doubling of the chicken's uropygial gland papilla

A new mutation that causes doubling of the uropygial gland (oil gland) papilla is described, and data that demonstrate its inherited basis are presented. This condition, which has been given the name "double oil gland papilla," varies in its expression: some individuals show only an indention of the papilla tip, while others exhibit a complete cleavage of the papilla such that two completely separate papillae project from a single oil gland. The data presented show that a single autosomal recessive gene, dgp, is the main determinant of this trait, but that its expression may also be influenced by background genetic factors as well as sex. Males more frequently are of the extreme doubling expression while females more frequently express the milder indented phenotype. Approximately 4% of mutant females are classified as normal. A linkage test with the rose comb gene showed independent segregation.     

The uropygial gland secretions of birds of the family sylviidae

The preen gland secretions from eight species of the genera Acrocephalus and Sylvia (Sylviidae, Passeriformes) mainly consist of monoester waxes. The fatty acids and alcohols are methyl-substituted at even numbered positions only. One of the methyl groups of the fatty acids is always located in the 2-position. Two patterns of methyl substitution are found for the alkanols: $\text{2-}\text{mono-}$, $\text{2,6-di-}$, and $\text{2,6,x-}\text{trimethyl}$ on the one hand, and 4-mono-, 4,8-di-, and 4,8,$\text{y-}\text{trimethyl}$ on the other. There is, however, no doubt in the uniformity of the family Sylviidae from the chemotaxonomical point of view; the waxes of the species investigated can be arranged in a gradual succession of substitution patterns. The monoester waxes of Sylviidae are similar to those found for the closely related family Turdidae.     

Chemical composition of uropygial gland secretions of owls

The compositions of the uropygial gland secretions of the long-eared owl, eagle owl, and barn owl have been determined. The waxes of the first two owls, which are closely related, are composed of 2-alkyl-substituted fatty acids and n- or monomethyl-branched alcohols with even-numbered branching positions. In addition, some dimethyl-substituted alkanols were observed. In contrast to these waxes, the secretion of the barn owl is composed of 3-methyl- and 3,5-, 3,7-, 3,9-, 3,11-, 3,13-, and 3,15-dimethyl-branched fatty acids and n- as well as monomethyl-substituted alkanols branched at positions 2, 3, and 4. The mass spectra of esters of 2-alkyl-substituted fatty acids are discussed.     

Plumage brightness and uropygial gland secretions in barn swallows

The uropygial gland has been hypothesized to play a role in sexual signaling through a "make-up" function derived from the effects of secretions from the gland on the appearanee of the plumage and bare parts of the body. Here we show that plumage brightness of dorsal feathers of individual barn swallows Hirundo rustica was greater in mated than in unmated individuals. In addition, plumage brightness in creased with colony size. Furthermore, plumage bright ness was positively correlated with the amount of wax in the uropygial gland, negatively correlated with time of sampling of uropygial wax (perhaps because more wax is present early in the morning after an entire night of wax production without any preening), and negatively correlated with the number of chewing lice that degrade the plumage. Experimentally preventing barn swallows from access to the uropygial gland reduced plumage brightness, showing a causal link between secretions from the uropygial gland and plumage brightness. These findings provide evidence consistent with a role of uropygial secretions in signaling plumage brightness.     

The chemical composition of uropygial gland secretions from ralliformes

The uropygial gland wax from rails contains ester waxes, triester waxes and triglycerides. The ester waxes are composed of mainly methyl-substituted fatty acids with predominantly n-alkanols. Methyl-branched alcohols are only found in minor amounts. The occurrence of 2,6,10- and 4,8,12-trimethyl-substituted acids can be used as chemotaxonomie markers. The triester waxes contain n-fatty acids, n-alkanols and alkyl-hydroxymalonic acids.     

Sex differences in the chemical composition of uropygial gland waxes in domestic ducks

Sexual differences in the chemical composition of the uropygial gland waxes in domestic ducks have been detected before the nesting period. 3-Hydroxy fatty acids containing diester waxes and significant differences in the composition of the fatty acid and alcohol moieties of the monoester waxes occur during February–June only in the female preen wax. Males as well as ducklings, however, show constant wax patterns. Moreover, no significant influence on wax composition of testosterone or estradiol, respectively in male or female ducklings could be verified.     

Sex recognition by odour and variation in the uropygial gland secretion in starlings

1.?Although a growing body of evidence supports that olfaction based on chemical compounds emitted by birds may play a role in individual recognition, the possible role of chemical cues in sexual selection of birds has been only preliminarily studied. 2.?We investigated for the first time whether a passerine bird, the spotless starling Sturnus unicolor, was able to discriminate the sex of conspecifics by using olfactory cues and whether the size and secretion composition of the uropygial gland convey information on sex, age and reproductive status in this species. 3.?We performed a blind choice experiment during mating, and we found that starlings were able to discriminate the sex of conspecifics by using chemical cues alone. Both male and female starlings preferred male scents. Furthermore, the analysis of the chemical composition of the uropygial gland secretion by using gas chromatography-mass spectrometry (GC-MS) revealed differences between sexes, ages and reproductive status. 4.?In conclusion, our study reveals for first time that a passerine species can discriminate the sex of conspecifics by relying on chemical cues and suggests that the uropygial gland secretion may potentially function as a chemical signal used in mate choice and/or intrasexual competition in this species.     

Composition of uropygial gland waxes in relation to the classification of some passerine birds

The uropygial gland waxes of Aegithalos, Certhia, Leiothrix, Mesia, Panurus, Paradoxornis, Regulus, Remiz and Siva are monoester waxes composed of 2-; 2,x-; 2,x,y-; and 2,x,y,z-methyl-branched acids and unbranched as well as monomethyl-branched alcohols. Dimethylbranched alcohols occur in traces. All waxes are very similar. Chemotaxonomically all birds investigated are closely related and well separated from the family Paridae (tits).