Journal of Experimental Zoology最新文献_第10页

Structure and function of the mammalian egg zona pellucida. 哺乳动物卵细胞透明带的结构与功能。

Journal of Experimental Zoology Pub Date : 1999-10-15

P Wassarman, J Chen, N Cohen, E Litscher, C Liu, H Qi, Z Williams

引用次数: 0

Meiosis activating sterols (MAS) and fertility in mammals and man. 减数分裂激活甾醇(MAS)与哺乳动物和人的生育。

Journal of Experimental Zoology Pub Date : 1999-10-15

A G Byskov, C Y Andersen, L Leonardsen, M Baltsen

{"title":"Meiosis activating sterols (MAS) and fertility in mammals and man.","authors":"A G Byskov, C Y Andersen, L Leonardsen, M Baltsen","doi":"","DOIUrl":"","url":null,"abstract":"In mammals two meiosis activating sterols (MAS) have been found to activate meiotic resumption in mouse oocytes, in vitro. FF-MAS (4, 4-dimethyl-5alpha-cholesta-8,14,24-triene-3beta-ol) was extracted from human preovulatory follicular fluid and T-MAS (4, 4-dimethyl-5alpha-cholest-8,24-diene-3beta-ol) from bull testicular tissue. Quite unexpected, these two sterols, which introduce the cholesterol biosynthetic pathway from lanosterol, may be locally acting substances with important physiological function for reproduction. FF-MAS and T-MAS are present in the preovulatory follicular fluid of different mammalian species and have the capacity to initiate resumption of meiosis in mouse oocyte cultured in the presence of hypoxanthine, a natural meiosis maturation inhibitor. FF-MAS is produced by the cumulus cells of intact oocyte-cumulus complexes upon FSH-stimulation and provides the oocyte with a go-signal for the resumption of meiosis. T-MAS constitutes the vast majority of MAS found in the mammalian testis and in the human ejaculate; in particular a high concentration is found in the spermatozoa. T-MAS may be produced by the spermatids and the presence of T-MAS in spermatozoa may suggest that T-MAS plays a role in fertilization by affecting the second meiotic division.J. Exp. Zool. (Mol. Dev. Evol.) 285:237-242, 1999.","PeriodicalId":15686,"journal":{"name":"Journal of Experimental Zoology","volume":"285 3","pages":"237-42"},"PeriodicalIF":0.0,"publicationDate":"1999-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21361429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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The ins and outs of meiosis. 减数分裂的来龙去脉

Journal of Experimental Zoology Pub Date : 1999-10-15

B Dale, M Marino, M Wilding

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Molecular diversity, localization, and biological actions of elasmobranch tachykinins. 弹性支速激素的分子多样性、定位和生物学作用。

Journal of Experimental Zoology Pub Date : 1999-10-01

J M Conlon

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Parathyroid hormone-related protein (PTHrP) in cartilaginous and bony fish tissues. 软骨和硬骨鱼组织中的甲状旁腺激素相关蛋白。

Journal of Experimental Zoology Pub Date : 1999-10-01 DOI: 10.1002/(sici)1097-010x(19991001)284:5<541::aid-jez10>3.3.co;2-v

M K Trivett, R A Officer, J G Clement, T I Walker, J M Joss, P M Ingleton, T J Martin, J A Danks

{"title":"Parathyroid hormone-related protein (PTHrP) in cartilaginous and bony fish tissues.","authors":"M K Trivett, R A Officer, J G Clement, T I Walker, J M Joss, P M Ingleton, T J Martin, J A Danks","doi":"10.1002/(sici)1097-010x(19991001)284:5<541::aid-jez10>3.3.co;2-v","DOIUrl":"https://doi.org/10.1002/(sici)1097-010x(19991001)284:5<541::aid-jez10>3.3.co;2-v","url":null,"abstract":"Tissues from a range of fish were examined for the presence of parathyroid hormone-related protein (PTHrP) to investigate PTHrP protein distribution and PTHrP gene expression in jawless fish, cartilaginous fish, and bony fish. Immunoreactive PTHrP was localized using antisera to N-terminal and mid-molecule regions of human PTHrP and PTHrP gene expression examined using a digoxigenin labeled riboprobe to a conserved region of the mammalian PTHrP gene. In all of the fish studied, PTHrP protein and messenger RNA (mRNA) were localized to the skin, kidney, and skeletal muscle, following the pattern seen in higher vertebrates. Additional sites of localization for both protein and mRNA included gill, nerve cord, and pituitary, as well as developing dermal denticles and rectal gland in the elasmobranch species. The sites of PTHrP distribution indicate that PTHrP may have roles in ionoregulation as well as growth and differentiation in fish, as has been suggested in higher vertebrates. The results imply that the distribution of PTHrP is widespread in fish and that there is homology between the PTHrP molecules found in humans and fish. The conservation of localization and possible similarity of the PTHrP molecules between tetrapods and fish suggests that PTHrP has a number of fundamental roles in vertebrates. J. Exp. Zool. 284:541-548, 1999.","PeriodicalId":15686,"journal":{"name":"Journal of Experimental Zoology","volume":"284 5","pages":"541-8"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21334864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Serum T(4) and serum T(3) concentrations in immature captive whitetip reef sharks, Triaenodon obesus. 圈养白鳍鲨幼鲨血清T(4)和血清T(3)浓度。

Journal of Experimental Zoology Pub Date : 1999-10-01

G L Crow, B Ron, S Atkinson, L E Rasmussen

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Structure of the thyroid gland, serum thyroid hormones, and the reproductive cycle of the Atlantic stingray, Dasyatis sabina. 大西洋黄貂鱼的甲状腺结构、血清甲状腺激素和生殖周期。

Journal of Experimental Zoology Pub Date : 1999-10-01

H Volkoff, J P Wourms, E Amesbury, F F Snelson

{"title":"Structure of the thyroid gland, serum thyroid hormones, and the reproductive cycle of the Atlantic stingray, Dasyatis sabina.","authors":"H Volkoff, J P Wourms, E Amesbury, F F Snelson","doi":"","DOIUrl":"","url":null,"abstract":"This study examines the role of the thyroid gland in the control of reproduction in the viviparous Atlantic stingray, Dasyatis sabina. Thyroid activity in individuals in different reproductive stages was assessed both by microscopic examination of the gland, and by analysis of circulating levels of thyroid hormones from the same individuals. The thyroid gland is a cylindric organ, embedded in a connective tissue capsule, and composed of follicles, i.e., monolayer spheres of thyroid epithelial cells. Stingray follicular cells possess several characteristic features, namely apical cilia and a well-developed endoplasmic reticulum. Cells vary in size and shape, according to the activity of the gland. No structural differences were observed between the thyroid glands of the two sexes. Both thyroid hormones, triiodothyronine, [T(3)], and thyroxine, [T(4)], were detected in the serum of all animals examined. Levels ranged from 1.3-2.6 microg/100 ml for total T(4), and from 1.2-2.6 ng/ml for total T(3). The T(4) levels did not vary significantly in any group. Immature individuals and females undergoing oogenesis had the lowest levels of circulating T(3) and mature females from ovulation throughout gestation had high thyroid gland activity and high levels of circulating T(3). J. Exp. Zool. 284:505-516, 1999.","PeriodicalId":15686,"journal":{"name":"Journal of Experimental Zoology","volume":"284 5","pages":"505-16"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21334860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Evaluation of thyroid hormone economy in elasmobranch fishes, with measurements of hepatic 5'-monodeiodinase activity in wild dogfish. 利用野生角鲨肝脏5′-单去碘酶活性的测定评价板鳃鱼的甲状腺激素经济性。

Journal of Experimental Zoology Pub Date : 1999-10-01

S C Leary, J S Ballantyne, J F Leatherland

{"title":"Evaluation of thyroid hormone economy in elasmobranch fishes, with measurements of hepatic 5'-monodeiodinase activity in wild dogfish.","authors":"S C Leary, J S Ballantyne, J F Leatherland","doi":"","DOIUrl":"","url":null,"abstract":"This paper reviews the current understanding of thyroid hormone economy and homeostasis in elasmobranch fishes and considers those measures of the activity of the hypothalamic-pituitary gland-thyroid gland-peripheral tissue axis that are necessary for adequate assessment of thyroid hormone physiology. In particular, we focus on the value of measuring hepatic 5'-monodeiodinase (5'-MDA) activity as an indicator of the animal's cellular production rate of the active thyroid hormone, triiodo-L-thyronine (T(3)). We also examine the characteristics of hepatic 5'-MDA activity, in vitro, in adult female dogfish (Squalus acanthias) collected from Passamaquoddy Bay, New Brunswick, Canada, and in the embryos that they were carrying. T(3) production from T(4) by hepatic homogenates in vitro was time- and temperature-dependent, and was enhanced by the presence of a thiol donor. Michaelis constant (K(m)) and maximum reaction velocity (V(max)) values were 3.8 x 10(-7) M and 0.29 nM T(3)/mg protein/hr, respectively. The inclusion of trimethylamine-N-oxide (TMAO) or a mixture of urea, TMAO, betaine and sarcosine significantly enhanced T(3) production. Hepatic 5'-MDA activity was depressed in fish fasted for 7 days. J. Exp. Zool. 284:492-499, 1999.","PeriodicalId":15686,"journal":{"name":"Journal of Experimental Zoology","volume":"284 5","pages":"492-9"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21334858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Regulation of interrenal gland steroidogenesis in the Atlantic stingray (Dasyatis sabina). 大西洋黄貂鱼(Dasyatis sabina)肾间激素生成的调控。

Journal of Experimental Zoology Pub Date : 1999-10-01

S Nunez, J M Trant

{"title":"Regulation of interrenal gland steroidogenesis in the Atlantic stingray (Dasyatis sabina).","authors":"S Nunez, J M Trant","doi":"","DOIUrl":"","url":null,"abstract":"The interrenal gland (the homologue of the mammalian adrenal cortex) of elasmobranchs (sharks, skates, and rays) produces 1alpha-hydroxycorticosterone (1alpha-B), which has been reported to function both as a gluco- and mineralocorticosteroid. In vitro synthesis of 1alpha-B by Atlantic stingray (Dasyatis sabina) interrenal glands was stimulated by short-term (2 hr) and long-term (24 hr) treatment with porcine adrenocorticotropic hormone (pACTH). Cycloheximide blocked the pACTH-induced effect on 1alpha-B synthesis, thus demonstrating that the mechanism for the short-term induction of steroidogenesis involved protein synthesis. However, gene transcription did not play a role in the short-term induction of 1alpha-B synthesis, as indicated by the lack of an effect with actinomycin D treatment. Long-term in vitro exposure to pACTH (but not short-term exposure) stimulated the synthesis of another steroid, 11-dehydrocorticosterone (A). This induction was partially blocked by cycloheximide and actinomycin D, which suggests enhanced expression of the 11beta-hydroxysteroid dehydrogenase gene. In addition, the 24-hr treatment with pACTH enhanced the activity of cytochrome P450 side chain cleavage several fold and doubled the activity of 3beta-hydroxysteroid dehydrogenase and cytochrome P450 21-hydroxylase in D. sabina interrenals, again suggesting the induction of steroidogenic genes. In contrast to other elasmobranch species, the salmon and human forms of angiotensin II had no effect on D. sabina interrenal steroidogenesis. J. Exp. Zool. 284:517-525, 1999.","PeriodicalId":15686,"journal":{"name":"Journal of Experimental Zoology","volume":"284 5","pages":"517-25"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21334861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Alterations in serum steroid concentrations in the clearnose skate, Raja eglanteria: correlations with season and reproductive status. 白鼻鳐血清类固醇浓度的变化:与季节和繁殖状态的相关性。

Journal of Experimental Zoology Pub Date : 1999-10-01 DOI: 10.1002/(sici)1097-010x(19991001)284:5<575::aid-jez13>3.3.co;2-9

L E Rasmussen, D L Hess, C A Luer

{"title":"Alterations in serum steroid concentrations in the clearnose skate, Raja eglanteria: correlations with season and reproductive status.","authors":"L E Rasmussen, D L Hess, C A Luer","doi":"10.1002/(sici)1097-010x(19991001)284:5<575::aid-jez13>3.3.co;2-9","DOIUrl":"https://doi.org/10.1002/(sici)1097-010x(19991001)284:5<575::aid-jez13>3.3.co;2-9","url":null,"abstract":"Serum steroid hormones in the peripheral circulation of the clearnose skate, Raja eglanteria, were measured at the time of capture and at various times throughout the year while the animals were maintained as a captive breeding population. These analyses demonstrate interesting correlations between changes in hormone concentrations and annual reproductive events. Animals were sampled once (78 females, 20 males) or multiple times (15 females). For both groups of females, 17beta-estradiol was detected throughout the year with significant elevations occurring during October and November when ovarian follicles begin to mature (as determined through necropsy examinations), and January and February when maximum mating activity is observed and egg laying begins. Testosterone and dihydrotestosterone concentrations were significantly elevated in females only during January and February. Testosterone elevations were synchronous with longer-term elevations in 17beta-estradiol in females sampled either once or repetitively. Testosterone concentrations in males were significantly elevated during times of maximum breeding activity compared to periods of sexual inactivity. Data from females sampled during five stages of the egg laying process, as defined by the position of palpable egg capsules within the reproductive tract, revealed that 17beta-estradiol was highest when egg capsules were forming in the nidamental gland (stage 2) or uterus (stage 3); testosterone and dihydrotestosterone were maximal when eggs were in the uterus (stage 3) or cloaca (stage 4); and progesterone was significantly elevated immediately after oviposition (stage 5), suggesting a possible role for progesterone in the regulation of sequential laying of egg pairs. J. Exp. Zool. 284:575-585, 1999.","PeriodicalId":15686,"journal":{"name":"Journal of Experimental Zoology","volume":"284 5","pages":"575-85"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21334237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0