Histochemical demonstration of the presence of serotonin in the hen (Gallus domesticus) reproductive tract

The purpose of the present study was to demonstrate visually and localize the presence of serotonin (5-HT) in the ovary and oviduct of the domestic hen using a histochemical Falck-Hillarp method. Experiments were carried out on White Leghorn laying hens with no egg in the shell gland. The specific yellow fluorescence, indicating the presence of 5-HT, was found both in the ovary and all examined oviductal parts. The strongest fluorescence was present in the ovarian stroma containing small follicles with a diameter under 4 mm. In the wall of the largest preovulatory follicle a very strong fluorescence was located mainly in the theca layer. In the oviductal parts, the intensity of 5-HT fluorescence in the infundibulum and magnum was fairly strong, whereas in the isthmus and shell gland it was weak. Fluorescence seen in the infundibulum, magnum, and isthmus was primarily localized along the luminal borders of the fold surface epithelium. In the shell gland 5-HT fluorescence was found within the uterine folds, especially in the tubular glands. Moreover, the presence of an egg in the definite oviductal segment (infundibulum or isthmus) increased the intensity of yellow fluorescence in this part.     

Immunohistochemical localization of a calcium pump and calbindin-D28k in the oviduct of the laying hen.

The localization of a plasma membrane calcium pump in the oviduct of the laying hen was investigated by immunohistochemical techniques, utilizing a monoclonal antibody (5F10) produced against the human erythrocyte calcium pump. This antibody was shown to react with an epitope of the pump in oviductal tissue, and prominent staining was observed on the microvilli of the tubular gland cells of the hen shell gland (uterus) and the isthmus. The Ca2+ pump was not detectable in the infundibulum or the magnum. Calbindin-D28k, also localized by immunohistochemical means, was observed to be present in the tubular gland cells of the shell gland and the distal isthmus (adjacent to shell gland) but not in either the proximal isthmus (adjacent to the magnum), the magnum or the infundibulum. The localization of the Ca2+ pump in the oviduct corresponds to known sites of mineral deposition during egg shell formation. The distribution of calbindin-D28k differed, co-localizing with the Ca2+ pump in the shell gland and distal isthmus but not in the proximal isthmus. This might reflect a greater rate of active Ca2+ secretion in the distal isthmus and shell gland as compared to the proximal isthmus.     

Immunohistochemical localization of a calcium pump and calbindin-D28k in the oviduct of the laying hen

Summary The localization of a plasma membrane calcium pump in the oviduct of the laying hen was investigated by immunohistochemical techniques, utilizing a monoclonal antibody (5F10) produced against the human erythrocyte calcium pump. This antibody was shown to react with an epitope of the pump in oviductal tissue, and prominent staining was observed on the microvilli of the tubular gland cells of the hen shell gland (uterus) and the isthmus. The Ca²⁺ pump was not detectable in the infundibulum or the magnum. Calbindin-D_28k, also localized by immunohistochemical means, was observed to be present in the tubular gland cells of the shell gland and the distal isthmus (adjacent to shell gland) but not in either the proximal isthmus (adjacent to the magnum), the magnum or the infundibulum. The localization of the Ca²⁺ pump in the oviduct corresponds to known sites of mineral deposition during egg shell formation. The distribution of calbindin-D_28k differed, co-localizing with the Ca²⁺ pump in the shell gland and distal isthmus but not in the proximal isthmus. This might reflect a greater rate of active Ca²⁺ secretion in the distal isthmus and shell gland as compared to the proximal isthmus.     

Histomorphological changes in the oviduct of the mallard (Aves: Anatidae)

Studies on histomorphometrical changes in different segments (infundibulum, magnum, isthmus, shell gland and vagina) of oviduct of mallard, Anas platyrhynchos during active and quiescent phases of the reproductive cycle have been made. The absolute and per cent length and width of each segment showed a marked change. The magnum showed an increase of 280 per cent. Of all the histological parameters studied the number and height of mucosal folds and mucosal epithelium showed more marked increase in all segments of oviduct. The size of tubular glands and frequency of ciliated and secretory cells were studied in relation to oviductal activity.     

Ultrastructural changes in the oviduct of the laying hen during the laying cycle

The ultrastructural changes occurring in the fully functional oviduct of Isa Brown laying hens were studied during various stages of the laying cycle. Hens were killed at different positions of the egg in the oviduct. The oviduct was lined by ciliated and non-ciliated cells (also referred to as granular cells). The granular cells in the infundibulum contributed to secretion during egg formation, whereas ciliated cells showed little evidence of secretion. Ultrastructural changes were recorded in the granular and glandular cells of the distal infundibulum. In the magnum, the surface ultrastructure revealed glandular openings associated with the ciliated and granular cells. Cyclic changes were recorded in the glandular cells of the magnum. With respect to the three observed types of glands, the structure of gland type A and C cells varied at different egg positions in the oviduct, whereas type B cells represented a different type of gland cell containing amorphous secretory granules. The surface epithelium of the isthmus was also lined by mitochondrial cells. Two types of glandular cell (types 1 and 2) were recorded in the isthmus during the laying cycle. Intracisternal granules were found in type 2 cells of the isthmus. A predominance of glycogen particles occurred in the tubular shell gland. The granular cells in the shell gland contain many vacuoles. During egg formation, these vacuoles regressed following the formation of extensive rough endoplasmic reticulum; the reverse also occurred. The disintegrated material found in the vacuoles may have been derived from the disintegrating granules. The Physiology Teaching Unit, University of New England, provided financial support to K. Chousalkar for this study.     

Comparative distribution of glycosaminoglycans and proteoglycans in the reproductive tissues of the female fowl

The objective of this work was to survey and compare the composition of the parts of the reproductive system of the female fowl in glycosaminoglycans and proteoglycans. Those parts analyzed were ovary, infundibulum, magnum, isthmus, shell gland and vagina. Methods of analysis included cellulose acetate electrophoresis, infrared spectroscopy, colorimetry, amino acid determination and scanning electron microscopy. Concentrations of glycosaminoglycans were higher in vagina, ovary, infundibulum and isthmus than in shell gland and magnum. Glycosaminoglycans may be important in those parts of the reproductive tract which contribute membraneous and mucosal material to the descending egg, and where fertilization of the egg occurs.     

Role of hydroxyl radical scavengers dimethyl sulfoxide,alcohols and methional in the inhibition of prostaglandin biosynthesis

Prostaglandin (PG) F_2α provoked a contraction of longitudinal tissue strips from the uterine, vaginal and isthmus regions of the chicken oviduct; no response was induced in longitudinal tissue strips from the magnum and infundibulum.PGE₂ induced a contraction of circular and longitudinal uterine strips and of circular strips from the isthmus and infundibulum. With both circular and longitudinal vaginal strips a relaxation was obtained. A dose-dependent response was observed with circular magnum strips: contraction with low doses and relaxation at higher doses. No response was obtained with longitudinal tissue strips from the isthmus, magnum and infundibulum.The possible influence of both prostaglandins in the mechanism of ovum transport and oviposition in the domestic hen is discussed.     

Effect of estrogen on angiotensin converting enzyme in immature quail oviduct.

Effect of oestradiol was studied on the angiotensin converting enzyme (ACE)--a component of renin angiotensin system, in oviduct of immature quails of 15 days of age. ACE was studied in whole oviduct, magnum, shell gland and the glandular epithelium of magnum and shell gland. It was found that whole oviduct had a significantly higher level of ACE in control than those treated with exogenous estrogen at three dose levels (200, 400 or 600 micrograms). ACE contents of whole muscle and glandular epithelium did not differ but magnum had higher ACE level than the shell gland. Results are explained on the basis of functional role of oviductal parts.     

Effect of prostaglandins on oviduct tone in the domestic hen in vivo

The effect of i.v. injected prostaglandins (PG) F₂α and E₂ on intraluminal pressure of the different oviductal parts (infundibulum, magnum, isthmus, uterus and vagina) was investigated in the domestic hen. PGF₂α induced only a pressure rise in all oviduct segments. Administration of PGE₂ resulted in variable changes in oviductal tone: pressure rise in the infundibulum; pressure increase often preceded by a small decrease in the magnum, isthmus and uterus; pressure decrease in the vagina and sometimes in the uterus. Simultaneous i.v. injection of both PG's induced mostly a decrease in vaginal tone. Intraluminal administration of PGF₂α or E₂ resulted only in an increase in uterine pressure.The observed effects on oviduct tone are discussed and a possible in intervention of both PG's in the mechanism of ovum transport and oviposition in the domestic hen is proposed.     

Seasonal changes in the oviduct of the pied myna (Aves: Sturnidae)

Study of the oviduct of the pied myna (Sturnus contra contra) throughout the year reveals that oviductal weight, length, surface epithelial height and glycogen content are low during August to January (nonbreeding phase), partially increase during February to April (pre-breeding phase), maximally increase in May (breeding phase) and decrease in June and July (post-breeding phase). In the nesting cycle, there is greatest growth in all the regions of the oviduct from early nest-building to the egg-laying period and this is followed by rapid involution during incubation and nestling periods. Some notable features in the oviduct of the pied myna are described: 1) All five regions of the oviduct (infundibulum, magnum, isthmus, uterus, and vagina) are clearly distinguishable when studied from serial sections of the oviduct even during the nonbreeding phase of the annual ovarian cycle. 2) There is a strong correlation between initiation of tubular gland formation and the onset of nestbuilding activity. 3) The distal part of the magnum is differentiated into a 'mucous region' having well developed basal nonciliated cells. 4) A sixth zone can be identified between the magnum and isthmus. Sperm hostlike glands exist at the cranial end of the zone. 5) Several circular epithelial invaginations are evident in the intermucosal folds and their size decreases in centripetal order in the vagina. 6) The pattern and degree of regression are different in various regions of the oviduct. A close synchrony between ovarian and oviducal cycles is indicated in the pied myna (Sturnus contra contra).     

Histology and functional morphology of the female reproductive tract of the tortoise Gopherus polyphemus

The oviducts of 25 tortoises (Gopherus polyphemus) were examined by using histology and scanning electron microscopy to determine oviductal functional morphology. Oviductal formation of albumen and eggshell was of particular interest. The oviduct is composed of 5 morphologically distinct regions; infundibulum, uterine tube, isthmus, uterus, and vagina. The epithelium consists of ciliated cells and microvillous secretory cells throughout the oviduct, whereas bleb secretory cells are unique to the infundibulum. The epithelium and endometrial glands of the uterine tube histologically resemble those of the avian magnum which produce egg albumen and may be functionally homologous. The isthmus is a short, nonglandular region of the oviduct and appears to contribute little to either albumen or eggshell formation. The uterus retains the eggs until oviposition and may form both the fibrous and calcareous eggshell. The endometrial glands are histologically similar to the endometrial glands of the isthmus of birds, which are known to secrete the fibers of the eggshell. These glands hypertrophy during vitellogenesis but become depleted during gravidity. The uterine epithelium may supply "plumping water" to the egg albumen as well as transport calcium ions for eggshell formation. The vagina is extremely muscular and serves as a sphincter to retain the eggs until oviposition. Sperm are found within the oviductal lumen and endometrial glands from the posterior tube to the anterior uterus throughout the reproductive cycle. This indicates sperm storage within the female tract, although the viability and reproductive significance of these sperm are unknown.     

Acid glycosidases in the isthmus of the hen oviduct and egg shell membranes

Specific activities of seven acid glycosidases: beta-hexosaminidase, alpha- and beta-galactosidase, alpha- and beta-mannosidase, alpha-glucosidase and alpha-fucosidase were determined in various parts of the domestic hen oviduct (infundibulum, isthmus, shell gland and vagina). The activity of most enzymes was the highest in the isthmus. Multiple forms of all acid glycosidases from the isthmus were separated by strong anion exchange chromatography at pH 6.0. The isoelectric points of the isthmus forms of beta-hexosaminidase, beta-galactosidase and alpha- and beta-mannosidase were determined by chromatofocusing. For the first time the high beta-galactosidase activity was found in hen egg shell membranes.     

Cell-specific and temporal aspects of gene expression in the chicken oviduct at different stages of the laying cycle

Egg formation and embryonic development occur as the yolk passes through the magnum, isthmus, and shell gland of the oviduct before oviposition in hens. The present study identified candidate genes associated with secretory function of the chicken oviduct after ovulation and contributing to egg formation and oviposition. Hens (n = 5 per time point) were euthanized to recover the reproductive tract when the egg was in the magnum (3 h after ovulation) and the shell gland (20 h after ovulation). Total RNA was extracted from each segment of the oviducts and subjected to Affymetrix chicken GeneChip analysis. Quantitative PCR and in situ hybridization analyses of selected genes confirmed the validity of the gene expression patterns detected using microarray analysis. In particular, ACP1, CALB1, CYP26A1, PENK, RCAN1 and SPP1 expression increased significantly in the shell gland between 3 h and 20 h postovulation, whereas only RCNA1 expression increased significantly in the magnum between 3 h and 20 h postovulation. Results of the high-throughput analysis revealed cell-specific and temporal changes in gene expression in the oviduct at 3 h and 20 h postovulation in laying hens provide novel insight into changes at the molecular and cellular levels of candidate genes related to formation of the egg and oviposition.     

Involvement of alpha 1- and alpha 2-adrenergic receptors in the hypothalamo-pituitary-ovarian axis of the domestic fowl, Gallus domesticus

The alpha 1-adrenergic receptor ligand, 3H-WB4101, and the alpha 2-adrenergic receptor ligand, 3H-para-aminoclonidine, were utilized at a 1.0 nM incubation concentration to determine relative alpha 1-and alpha 2-adrenergic receptor binding by cell membranes from selected tissues within the brain, ovary and oviduct of the domestic fowl. Significant specific alpha 1-adrenergic binding was observed in the hypothalamus, anterior pituitary, pineal, cerebrum and cerebellum but only the cerebrum had significant alpha 2-receptor binding. Significant levels of alpha 1-adrenergic binding were observed in the granulosa cells of the three largest ovarian follicles and in the postovulatory follicle. Significant specific alpha 2-adrenergic binding was measured in the infundibulum, magnum, isthmus and shell gland of the oviduct. The physiological implications of alpha-adrenergic receptors in these tissues are discussed.     

Zinc Secretion in the Oviduct of the Coturnix Quail

The oviduct from laying quail were used to investigate mechanisms of trace mineral secretion and the possible role of metallothionein in this process. Secretion of zinc occurred maximally at pH 5.4, which is close to the normal pH of the oviduct. Secretion occurred to a much greater extent in the isthmus and shell gland than in the magnum, the major protein-secretory section of the oviduct. Intraperitoneal administration of cadmium resulted in a marked reduction in Zn secretion from the oviduct of laying quail. This effect could not be correlated with metallothionein since metallothionein could not be detected in any section of the oviduct in control or Cd-induced quail. Small-molecular-weight metal-binding ligands were present in the isthmus and shell gland, which may play a role in trace mineral mobilization. Histological evaluation by light and elelctron microscopy show that Zn is transported from the smooth muscle cells through the connective tissue matrix in the extracellular space to the epithelial goblet cells. Presumably, Zn and other trace minerals are secreted from the secretory goblet cells into the egg.     

Smooth muscle of the quail oviduct functions as a stretch receptor during ovum transport

The present experiments were conducted to test the hypothesis that ovum transport in the quail oviduct is regulated by a time-dependent, stretch-mediated feedback cycle which alters the frequency of contractions. According to this hypothesis, a ligature preventing the forward movement of ovum should reverse the direction of the feedback cycle and an artificial ovum should be transported like the normal ovum. When the ligature was placed in the borderline between magnum and isthmus, it caused the reversal of transport direction after a delay of several minutes. Once the direction had changed, it persisted until the ovum was expulsed through the fimbrial end or until a second reversal was caused by either a second ligature or a minor mechanical impediment at the proximal end of the magnum. The ovum was transported between the ligatures at the mean speed of 1.7 +/- 0.17 mm/min (n = 7) until the ovum broke. An artificial ovum placed in the proximal magnum from which the natural ovum had been removed, was transported like the natural ova. Myoelectrical activity recorded with suction electrodes was statistically similar in both types of experiments and the direction of the frequency gradient changed when the transport direction was reversed. The frequency of the electrical activity of oviductal smooth muscle was significantly higher behind the ovum than in its front whether ova were transported in the direction of shell gland or infundibulum; in the segment maximally stretched by the ovum the activity was significantly lower than in other segments. These observations confirmed the hypothesis and suggest that the quail oviduct functions like a stretch receptor.     

Localization of osteopontin in oviduct tissue and eggshell during different stages of the avian egg laying cycle

The avian eggshell is an acellular bioceramic containing organic and inorganic phases that are sequentially assembled during the time the egg moves along the oviduct. As it has been demonstrated in other mineralized tissues, mineralization of the eggshell is regulated by extracellular matrix proteins especially the anionic side chains of proteoglycans. Among them, osteopontin has been found in the avian eggshell and oviduct. However, its precise localization in the eggshell or in different oviduct regions during eggshell formation, nor its function have been established. By using anti-osteopontin antibody (OPN 1), we studied its immunolocalization in the isthmus, red isthmus and shell gland of the oviduct, and in the eggshell during formation. In the eggshell, osteopontin was localized in the core of the non-mineralized shell membrane fibers, in the base of the mammillae and in the outermost part of the palisade. In the oviduct, OPN 1 was localized in the ciliated epithelial but not in the tubular gland cells of the isthmus, in the ciliated epithelial cells of the red isthmus, and in the non-ciliated epithelial cells of the shell gland. The occurrence of osteopontin in each of the oviduct regions, coincided with the concomitant presence of the egg in such region. Considering the reported inhibitory function of osteopontin in other mineralized systems, together with its main occurrence in the non-mineralized parts of the eggshell and at the outermost part of the shell, suggests that this molecule could be part of the mechanism regulating the eggshell calcification.     

Morphometric and ultrastructural features of the mare oviduct epithelium during oestrus

Morphometric, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) investigations have displayed regional differences in the mare oviductal epithelium. The entire mucosa of the oviduct was lined with a pseudostratified epithelium, which consisted of two distinct cell types, ciliated and non-ciliated. Ciliated cells were predominant in the three different segments of the oviduct and their percentage increased from fimbriae to ampulla and significantly decreased in the isthmus. SEM revealed in the infundibulum finger-like mucosal folds, some of them interconnected, in the ampulla numerous and elaborated branched folds of the mucosa, whereas the isthmus displayed a narrow lumen, short and non-branched mucosal folds. In the ampulla and isthmus the majority of non-ciliated cells showed apical blebs provided or not of short microvilli. TEM displayed different ultrastructural features of ciliated and non-ciliated cells along the oviduct. Isthmus ciliated cells presented a more electron-dense cytoplasm than in infundibulum and ampulla cells and its cilia were enclosed in an amorphous matrix. The non-ciliated cells of infundibulum did not contain secretory granules but some apical endocytic vesicles and microvilli coated by a well developed glycocalyx. Non-ciliated cells of ampulla and isthmus contained secretory granules. Apical protrusions of ampulla displayed two types of secretory granules as well as occasional electron-lucent vesicles. Isthmus non-ciliated cells showed either electron-lucent or electron-dense cytoplasm and not all contained apical protrusions. The electron-dense non-ciliated cells displayed microvilli coated with a well developed glycocalyx. Three types of granules were observed in the isthmus non-ciliated cells. The regional differences observed along the epithelium lining the mare oviduct suggest that the epithelium of the each segment is involved in the production of a distinctive microenvironment with a unique biochemical milieu related to its functional role.     

北京鸭产卵期输卵管管状腺细胞超微结构研究

用电子显徽镜对北京鸭输卵管管状腺细胞进行观察。鸭输卵管由五部分组成:漏斗、蛋白分泌部、峡部、壳腺和阴道。蛋白分泌部的管状腺细胞有四种类型。A型细胞有电子密度深色颗粒;B型细胞充满了无定型低电子密度物质;C型细胞具有非常明显的粗面内质网和高尔基复合体;D型细胞是由致密的颗粒和低电子密度的颗粒所组成,腔内充满分泌颗粒。我们在这篇文章中分析了蛋白分泌周期的四个不同阶段。