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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Golden hamster spermatozoa in various segments of the excurrent duct system were studied by freeze-fracture with and without filipin treatment. Two types of regular IMP (intramembranous particle) patterns temporarily appear on the plasma membrane covering the sperm head. One is a hexagonal arrangement seen in the acrosomal region, and the other is a linear arrangement near the posterior ring. Both patterns are seen in the spermatozoa from the corpus epididymidis. The FSC (filipin-sterol complex) density in the plasma membrane covering the acrosome increases from about 400 to 500 FSC/microns2 during epididymal passage. In this region, the majority of the membrane sterols appears to reside on the outer leaflet of the lipid bilayer. When the spermatozoa reach the cauda epididymidis, FSCs in the outer acrosomal membrane virtually disappear from the apical segment, while they increase in the middle segment (250 FSC/microns2). These observations are discussed in relation to epididymal maturation.
J Ultrastruct Mol Struct Res 1988 Jul
PMID:Changes in the distribution of intramembranous particles and filipin-sterol complexes during epididymal maturation of golden hamster spermatozoa. 320 59

A composite androgen receptor DNA sequence 4,181 base pairs in length was determined from three cDNA clones isolated from a rat epididymal bacteriophage lambda gt11 library. An open reading frame of 902 amino acids encodes a protein of 98,227 mol wt. Structural domains characteristic of the steroid receptor family include an amino-terminal region with five repeated amino acid motifs, a central DNA-binding domain homologous with other steroid receptors, and a carboxyl-terminal steroid-binding region. A receptor cDNA probe used in Northern blot analysis hybridized with a predominant 10-kilobase androgen receptor mRNA in male reproductive tissues of the rat. Autoregulation of androgen receptor mRNA was indicated in rat ventral prostate by an increase in the level of 10-kilobase mRNA after castration and suppression of receptor mRNA upon androgen restimulation. A 15 amino acid peptide with sequence derived from the deduced androgen receptor sequence was synthesized and used as immunogen in raising receptor antibodies in rabbits. Antisera reacted with high titer against the synthetic peptide by enzyme-linked immunosorbent assay and against the native [3H]dihydrotestosterone-labeled androgen receptor as evidenced by an increase in receptor sedimentation rate determined by sucrose gradient centrifugation. Immunocytochemical staining localized the androgen receptor to epithelial cell nuclei in rat ventral prostate.
Mol Endocrinol 1988 Dec
PMID:The rat androgen receptor: primary structure, autoregulation of its messenger ribonucleic acid, and immunocytochemical localization of the receptor protein. 321 67

Epididymal adipose tissue in the rat is generally considered to be "pure" white adipose tissue (WAT) with a characteristic structure and function. Previous studies in cats have, however, indicated that adipose tissue with the morphological appearance of WAT could be converted into a tissue with the morphological appearance of brown adipose tissue (BAT) by intermittent cold stress. The present electron microscopic and morphometric study describes the effect of intermittent cold stress on the epididymal WAT of young rats. The tissue volume decreased markedly as did the lipid content. The mitochondrial volume increased dramatically. The extracellular matrix was vastly reduced as was the thickness of the plasma membrane, and the number of gap junctions between adipocytes increased markedly. Indications of neoinnervation and neovascularization were observed. A great abundance of preadipocytes indicated proliferative activity of the endothelium. The low amount of lipid droplets and a relative abundance of smooth and rough endoplasmic reticulum. Golgi apparatus, and lysosomes in the epididymal WAT of cold-stressed rats gave the cells the morphological appearance of young adipocytes or preadipocytes whereas the hypertrophic and hyperplastic mitochondria, the relative paucity of ribosomes on lipid droplet membranes, and the increased innervation and vascularization gave the cells the morphological characteristics of brown adipose tissue.
J Ultrastruct Mol Struct Res
PMID:Epididymal white adipose tissue after cold stress in rats. I. Nonmitochondrial changes. 326 8

The effect of halothane on isoproterenol-stimulated lipolysis was determined in isolated rat epididymal fat cells. The maximal lipolytic response (Emax) activated by isoproterenol was 350 +/- 61 nmol of glycerol/10(5) cells/hr with an EC50 of 5.1 X 10(-9) M. When the adipocytes were simultaneously bubbled with 2.5% halothane, the Emax decreased to 158 +/- 43 nmol of glycerol/10(5) cells/hr and the dose response curve for isoproterenol was shifted to the right (EC50 3.5 X 10(-8) M, p less than 0.05). When lipolysis was maximally stimulated with (-)-isoproterenol (10(-6)M), the inhibitory effect of halothane was found to be both dose dependent (IC50 approximately 2.5%, v/v) and reversible following washout. Neither the nonhydrolyzable cAMP analog, 8-(4-chlorophenylthio) adenosine 3',5'-cyclic monophosphate (2 X 10(-3)M), nor forskolin (10(-6) M) was able to normalize lipolysis in the presence of halothane. The activation of cAMP-dependent protein kinase (EC 2.7.1.37) activity by isoproterenol was not different in halothane-exposed cells when compared to unexposed cells. When control adipocytes were exposed to isoproterenol (10(-6) M), there was a 2.5-fold increase in the activity of hormone-sensitive lipase (EC 3.1.1.3) from 0.64 +/- 0.13 to 1.53 +/- 0.32 pkat (pmol/sec) per mg (p less than 0.005, n = 10). However, in the presence of halothane (2.5%, v/v) isoproterenol stimulation of hormone-sensitive lipase was attenuated by 50% to values of 1.06 +/- 0.23 pkat/mg (p less than 0.01, n = 10). Halothane had no direct inhibitory effect on hormone-sensitive lipase since this enzyme's activity was unaffected when homogenates of isoproterenol-stimulated control cells were incubated with halothane. These studies suggest that halothane impairs the activation of hormone-sensitive lipase by cAMP-dependent protein kinase and in this manner inhibits beta-adrenergic-stimulated lipolysis.
Mol Pharmacol 1988 Mar
PMID:Mechanism of halothane-induced inhibition of isoproterenol-stimulated lipolysis in isolated rat adipocytes. 335 97

Testicular damage was induced in rats by respiratory treatment with n-hexane at a concentration of 5000 ppm. The earliest lesions were observed immediately after 24 hr of continuous treatment, and involved primary spermatocytes from the leptotene to the middle pachitene stages and spermatids at late stages of maturation; at the same time numerous exfoliated, injured germ cells reached the epididymis. After the 24-hr treatment was suspended, damage to the seminiferous epithelium increased for the first 7 days, while the epididymis showed also focal infiltration by inflammatory cells; recovery was completed from Days 14 to 30. Intermittent treatment (16 hr/day, 6 days/week) at the same concentration of 5000 ppm for up to 6 weeks induced progressive increases in testicular and epididymal lesions, which, after 5 weeks (when most animals began to show clinical symptoms of polyneuropathy), reached aplasia of the germinal epithelium involving also the spermatogonia. Recovery from clinical symptoms was not paralleled by a regression of testicular pathology. On the contrary, after interruption of the treatment, the testicular lesions became increasingly severe, up to complete atrophy of the seminiferous tubules, suggesting an irreversible sterility of the treated animals. Pair-fed controls did not show histological alterations of the testis or epididymis.
Exp Mol Pathol 1987 Apr
PMID:Effects of respiratory treatment with N-hexane on rat testis morphology. I. A light microscopic study. 355 33

Chinese hamster spermatozoa during epididymal maturation were examined by thin sectioning, freeze-fracture, and surface replica. Membrane-limited vesicles and tubules (MVTs) attach to the plasma membrane over the acrosome of the spermatozoa in the distal caput through proximal cauda epididymidis. The origin of these MVTs is likely to be spermatozoa degenerating in the epididymal lumen. The attachment of MVTs to the plasma membrane seems to be mediated by a paste-like substance covering the plasma membrane. A parallel striation pattern of intramembranous particles (IMPs) is seen in the plasma membrane of almost the entire postacrosomal region of the epididymal spermatozoa. The patterned domain begins to appear in the proximal caput epididymidis. The number and density of IMPs in the plasma membrane of the postacrosomal region increases with the development of striated pattern of IMPs in this region. In the cauda epididymidis, the redundant nuclear envelope elongates to form a shirt-like membrane covering the mitochondrial sheath. The elongated portion of the nuclear envelope is devoid of nuclear pores and has few IMPs.
J Ultrastruct Mol Struct Res
PMID:Membrane changes in Chinese hamster spermatozoa during epididymal maturation. 368 Oct 22

The effect of PMHI on the epididymis and accessory sex glands (ventral prostate, seminal vesicle, and coagulating gland) was studied in a wild rodent, the bandicoot rat. Animals were given a single subcutaneous injection of PMHI (150 mg/kg body wt) and were killed 2, 10, or 30 days later. Treatment of PMHI resulted in severe alterations in the epididymis of the bandicoot rat with no apparent effect on accessory sex glands except for a transitory decrease in epithelial height of the seminal vesicle and in peripheral acini of the ventral prostate. Changes in the epididymis included a marked involution of the caput, Zone I in particular, formation of sperm granulomata, and the distension of the "clear" cells in the caudal portion of the duct. Sperms progressively disappeared from the lumen and by Day 30, the cauda epididymis became completely azoospermic. It appears that the epididymal lesions produced by this compound may play a contributory role to induce infertility in the bandicoot rat.
Exp Mol Pathol 1986 Apr
PMID:Effect of DL-6-(N-alpha-pipecolinomethyl)-5-hydroxyindane maleate (PMHI) on the reproductive system of a wild rat, Bandicota bengalensis. II. Epididymis and accessory sex glands. 369 37

Interpretation of the experimental literature on epididymal glycerophosphorylcholine metabolism according to a recently proposed de novo pathway for the synthesis of acyl-specific phosphatidylcholine suggests that epididymal glycerophosphorylcholine is an intermediate of this proposed pathway. This glycerophosphodiester is postulated to be utilized by spermatozoa to synthesize docosahexaenoic phosphatidylcholine, proposed to be required for the development of sperm motility. A defect in glycerophosphorylcholine synthesis might be responsible for some forms of asthenozoospermia.
Mol Cell Biochem 1985 Nov
PMID:Synthesis of highly unsaturated phosphatidylcholines in the development of sperm motility: a role for epididymal glycerol-3-phosphorylcholine. 390 9

Rat epididymal tubules maintained in organ culture for 3 or 7 days in media containing androgen showed a marked increase in the incorporation of radioactive amino acids and uridine into acid insoluble material. When the tubules were exposed to these hormones for brief periods, the incorporation of precursors was inhibited initially. In studying the time course of binding of 3H testosterone to the cytoplasmic receptor, a significant amount of radioactivity bound to the receptor was detected only after 12 hr of exposure to the hormone which increased three-fold after 24 hr. The time lag in the binding corresponded closely to the shortest times of observed hormone action wherein a significant increase in the incoporation of uridine (16 hr) and amino acids (24 hr) was produced. Evidence is presented demonstrating that testosterone is bound with high affinity by components of the fetal calf serum present in the culture medium.
Curr Top Mol Endocrinol 1974
PMID:Studies on the correlation between androgen binding and activation of rat epididymal tubules in culture. 447 76

Cells isolated enzymically from seminal vesicles and epididymides of normal and castrated rats were shown by electron microscopy to be intact and representative of the tissue. The cells synthesize and secrete tissue-specific proteins. Short-term incorporation of [3H]uridine and [35S]methionine was measured to determine the effects of castration on RNA and protein synthesis. Epididymal cells and tissue incorporated uridine at similar rates which were unaltered by castration. Similarly castration failed to diminish uridine incorporation by seminal vesicle cells and tissue. Therefore, androgens may principally control RNA degradation. A similar situation pertained to methionine incorporation by epididymal cells and tissue so here too control may be via protein degradation. In contrast, castration greatly decreased methionine incorporation by seminal vesicle tissue but not by isolated cells. Isolated cells were more active than in tissue, particularly those from castrated rats, and may be released from stromal-epithelial interactions and controls.
Mol Cell Endocrinol 1981 Aug
PMID:Isolation of cells from rat seminal vesicles and epididymis and their use in studying androgen action. 616


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