Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.1 (alkaline phosphatase)
 47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The three capillary parts of the microvasculature of the human testis, namely the arterial side inter-Leydig cell capillaries, the intramural capillaries, and the venous side inter-Leydig cell capillaries, were studied in detail by dual detection of alkaline phosphatase enzyme activity and endothelial marker immunoreactivity, and by means of light- and transmission-electron microscopy. Alkaline phosphatase enzyme activity was seen in intertubular arterioles, capillaries, and venules, and in intramural capillaries of the human testis, whereas the lamina propria of human seminiferous tubules showed no staining. Alkaline phosphatase enzyme activity and the endothelial marker detected by the Qbend 30 antibody co-existed within the endothelial cells of the microvasculature. Electron-microscopically, the endothelial cells of the arterial and venous side inter-Leydig cell capillaries, and of the intertubular capillaries free of Leydig cells were of the continuous type without fenestrations (A-1-alpha type). The intramural capillaries consisted of non-fenestrated (A-1-alpha type) and fenestrated sections (A-2-alpha type). The fenestrations faced the germinal epithelium. Capillaries with a continuous non-fenestrated endothelium contained a large number of transcytotic vesicles and channels. These were numerous in the endothelial cells of the inter-Leydig cell capillaries and the non-fenestrated part of the intramural capillaries. Capillaries partly ran in between the layers of the lamina propria and therefore represented the capillarization of the seminiferous tubules. Thus the multilayered lamina propria probably requires its own capillary supply to allow rapid exchange between the microvasculature and the epithelium of the human seminiferous tubules.
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PMID:Capillaries in the lamina propria of human seminiferous tubules are partly fenestrated. 878 Dec 16

Two enriched populations of Leydig cells (hLCI and hLCII) have been characterized in human testes; it is noteworthy, that in the presence of hCG the steroid ouput is higher in hLCII when compared to hLCI; conversely, the basal production of steroids is greater in hLCI than in hLCII. The addition of increasing amounts of seminiferous tubule-conditioned medium to the purified Leydig cells leads to a dose-related enhancement of the steroid production in both Leydig cell fractions under basal and hCG-stimulated conditions. It is therefore obvious that a paracrine factor (or factors) from seminiferous tubular origin influences positively and with a high efficiency the human Leydig cell function. The human Sertoli cell synthesizes lactate, estradiol-17beta and several proteins, namely transferrin, ferritin and inhibin. In the presence of germ cells the Sertoli cell production of estradiol-17beta is decreased whereas the transferrin and inhibin outputs are enhanced. In addition the lactate dehydrogenase, gamma-glutamyl transpepetidase, alkaline phosphatase and creatine phosphokinase activities have been quantitated in various human Sertoli cell preparations. It should be kept in mind that germ cells exert an important influence on the adult Sertoli cell secretory activity through either direct contact and/or via secreted factors; moreover germ cells potentialize the stimulating effect of FSH on the Sertoli cell function and indirectly the Leydig cell output of testosterone via the Sertoli cell secretion of paracrine factor(s).
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PMID:Paracrine control of human Leydig cell and Sertoli cell functions. 896 55

A morphological study of the biological, histologic, and histochemical effects of vasectomy on albino rats is presented. No marked differences between vasectomized rats and the control group in the biological parameters of body weight and the weights of the adrenal glands, kidneys, prostate gland, seminal vesicles, and testes were observed. No changes in the frequency of copulation were noted. Histologic study of the liver, adrenal glands, kidneys, prostate gland, seminal vesicles, vas deferens, and epididymis showed no marked changes. Some testes of the vasectomized rats were considered inferior, though spermatogenesis was normal. No Leydig cell abnormalities were observed. The reactive pattern of the alkaline phosphatase staining of cells and tissue from the liver, adrenal glands, kidneys, prostate gland, seminal vesicles, vas deferens, epididymis, and testes showed similar metabolic activity in the vasectomy group and the control group. It was concluded that vasectomy does not result in the atrophy of the seminiferous tubules.
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PMID:Studies on vasectomy. 1217 9

In order to assess the potential chronic toxicity and tumorigenicity of ammonium perfluorooctanoate (APFO), a 2-year dietary study was conducted with male and female rats fed 30 ppm or 300 ppm (approximately 1.5 and 15 mg/kg). In males fed 300 ppm, mean body weights were lower across most of the test period and survival in these rats was greater than that seen either in the 30 ppm or the control group. Non-neoplastic effects were observed in liver in rats fed 300 ppm and included elevated liver weight, an increase in the incidence of diffuse hepatocellular hypertrophy, portal mononuclear cell infiltration, and mild hepatocellular vacuolation without an increase in hepatocellular necrosis. Mean serum activities of alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase were elevated up to three times the control means, primarily at the 300 ppm dose. A significant increase in Leydig cell tumors of the testes was seen in the males fed 300 ppm, and tumors of the liver and acinar pancreas, which are often observed in rats from chronic exposure to peroxisome proliferating agents, were not observed in this study. All other tumor types were those seen spontaneously in rats of this stock and age and were not associated with feeding of APFO.
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PMID:Chronic dietary toxicity and carcinogenicity study with ammonium perfluorooctanoate in Sprague-Dawley rats. 2253 2


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