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At least 793 records · Page 44Linked to original sources
PubMed1991

Efferent ductules of the boar--a morphological study.

The efferent ductules of the boar were investigated by means of corrosion casts, light microscopy, scanning and transmission electron microscopy. They arise from an extratesticular rete and constitute the major, caudolateral part of the ascending limb of the caput epididymidis. Ductules may be subdivided into three segments: a slightly undulating testicular segment, a highly coiled intermediate segment and a moderately coiled epididymal segment. A decrease in diameter is particularly marked from the intermediate to the epididymal segment. The epithelial transitions from the extratesticular rete to the efferent ductules and from these to the epididymal duct are clearly demarcated. The epithelium of the efferent ducts consists of principal and ciliated cells. Mononuclear leukocytes are found in the basal half. Ultrastructural evidence supports a strong absorptive activity of principal cells. Apical protrusions are not considered to be a proof of apocrine secretion but rather seem to be artifacts. The nature of membrane-bound granules of variable density remains speculative.

Animals↗
PubMed2006

Epithelial trafficking of Sonic hedgehog by megalin.

We present here evidence of in vivo epithelial endocytosis and trafficking of non-lipid-modified Sonic hedgehog (ShhN) when infused into rat efferent ducts via microinjection. Initially, exogenous ShhN is detected in endocytic vesicles and early endosomes located near the apical plasma membrane of non-ciliated cells. Within 30-60 min following infusion, ShhN can be detected in lysosomes and at basolateral regions of non-ciliated cells. Basolaterally, ShhN was observed along the extracellular surfaces of interdigitated plasma membranes of adjacent cells and in the extracellular compartment underlying the efferent duct epithelium. Uptake and subcellular trafficking of infused ShhN by non-ciliated cells could be blocked by either anti-megalin IgG or the megalin antagonist, RAP. Ciliated cells, which do not express megalin, displayed little if any apical internalization of ShhN even though they were found to express Patched-1. However, ShhN was found in coated pits of lateral plasma membranes of ciliated cells as well as in underlying endocytic vesicles. We conclude that megalin-mediated endocytosis of ShhN can occur in megalin-expressing epithelia in vivo, and that the internalized ShhN can be targeted to the lysosome or transcytosed in the plane of the epithelium or across the epithelium. These findings highlight the multiple mechanisms by which megalin may influence Shh morphogen gradients in vivo.

Animals↗
PubMed1981

High-resolution autoradiography of new formed proteins in the epididymis after incorporation of tritiated amino acids.

The synthesis and excretion of newly formed proteins in the principal cells of the head, body, and tail of the epididymis were studied by quantitative autoradiography in light and electron microscopy. Adult mice were killed from 5 min to 6 hr after intravenous injection of tritiated leucine, lysine, and arginine. The labels were taken up early and in greater amounts in the principal cells of the head. Radioactivity decreased in the cells of all three segments throughout the first hour following administration of the tracers. Thereafter, it increased in the lumen. High-resolution analysis showed successive peaks of relative concentration of the labels over the endoplasmic reticulum, Golgi apparatus, and apical plasma membrane, thus confirming that protein synthesis and excretion follow the usual pathway in the principal cells all along the epididymis. However, since a radioactivity peak occurred as early as 15 min over the apical membrane of cells in the head, it is likely that part of the endoplasmic reticulum-canalicular and poor in polysomes-is involved independently in the synthesis and rapid transport of newly formed proteins.

Amino Acids↗
PubMed1983

[Determination of substances inhibiting and stimulating the binding of FSH to its receptors].

We describe a method to estimate binding of human 125I-FSH to a preparation of bovine testicular receptors. Various experimental conditions are tested and the validity of the method is demonstrated. Using this method, the presence of biological substances modifying the FSH binding is measured in various fractions of ram retetestis fluid submitted to several steps of purification by chromatography. FSH receptor binding inhibitor (FSHRBI) activity is obtained in a low molecular weight fraction and FSH receptor binding stimulator activity in a larger one. These cybernin activities are isolated in fractions different from the ones observed with inhibin and GnRH like activities.

Animals↗
PubMed1983

Peristaltic transport of a physiological fluid. Part - III. applications.

The models of peristaltic flow in non-uniform and uniform tube and channel, developed in the companion papers, Part I and Part II, are applied and compared with the observed flow rates in vas deferens of rhesus monkeys, the small intestine, and the ductus deferens of the male reproductive tract.

Animals↗
PubMed1988

Studies of fluid and spermatozoal transport in the extratesticular genital ducts of the Japanese quail.

Stereological studies of the spermatic ducts of the quail were carried out for comparison between different parts of the system and those of other species, and to provide a basis for future physiological studies. Duct length, surface areas and volumes of various components of the ducts were determined. Values were subsequently used to calculate net fluxes of fluid across the duct epithelium, spermatozoal velocity and the distribution of spermatozoa throughout the system. It was concluded that the extratesticular spermatic ducts are divided into 2 main parts: (1) the ductuli efferentes where spermatozoa spend a brief period (8 minutes) and which are adapted for considerable net fluid reabsorption (100 microliters/cm2/h), and (2) the connecting ducts, ductus epididymidis and ductus deferens where spermatozoa spend a longer period (24 hours) and which are involved in little net fluid transport (0.14-2.1 microliter/cm2/h). Most spermatozoa (92.3%) are located in the ductus deferens. The velocity of spermatozoal transport is much the same through the quail spermatic ducts (0.37 mm/min) as through the mammalian epididymis, the difference between classes in the duration of spermatozoal transport being due to differences in the distance that they travel. In a comparison between estimates of spermatozoal concentration using stereological methods and direct counts of spermatozoa in samples collected using micropuncture procedures it was concluded that both methods gave similar results.

Animals↗
PubMed1986

The postnatal maturation of efferent tubules in the rat: a light and electron microscopy study.

The postnatal maturation of the epithelium and tubule wall of efferent tubules in the rat was investigated by light and transmission electron microscopy, from birth to 50 days of age, when sperms were released from the seminiferous tubules and appeared in the genital duct. At the end of the first week of life, an endocytotic apparatus is differentiated in the epithelial cells. During the third week of life, efferent tubules developed specializations for the transport of sperms and fluids, namely the appearance of ciliated elements interspersed among the principal cells of the epithelium, and differentiation of myoid elements in the tubule wall. The appearance of specializations related to endocytosis and fluid transport across the epithelium preceded the canalization of the seminiferous cords which, in fact, is reported to appear at the end of the second week of life in the rat, along with the initial secretion of testicular fluid. This suggested that the maturation of efferent tubules is not triggered by the passage of testicular fluid, as surmised for the postnatal differentiation of caput epididymis. The postnatal maturation of efferent tubules was almost complete 35 days after birth. The appearance of sperms in the genital duct of 50-day-old animals was not associated with any remarkable structural change.

Animals↗