ISSN:0022-104X    

DOI:10.1002/jez.1402560402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe use of unconventional organisms in experimental research is a timely subject that impacts upon current science policy in the areas of animal welfare, biodiversity, and biotechnology. Many recent reports have recommended a reduction in the use of mammals in biomedical research to promote animal welfare by utilizing alternative methods and unconventional model organisms. Currently we lack adequate models for all the biological phenomena worthy of study. Biologists must continue to take advantage of the functional biodiversity of organisms not only to identify new model organisms for studying more optimally those life processes we know something about, but also to discover entirely new biological principles, processes, and products. Increased emphasis on the need to preserve the diversity of life also requires more knowledge of the comparative biology of processes such as reproduction, growth, defense mechanisms, and nutrition. The functional biodiversity of life can be exploited not only for fundamentally new biological insights, but also for expanding the knowledge base needed for commercial biotechnology. There is a critical need of commercial biotechnology for basic functional information on more species, especially microorganisms and plants. The knowledge of biodiversity will mean little to most of mankind unless the motivation exists to use it for commercial benefit.

ISSN:0022-104X    

DOI:10.1002/jez.1402560403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractEstrogen formation in brain and pituitary mediates certain androgen actions in central targets. Goldfish (Carassius auratus) and quail (Coturnix coturnix japonica) have been advantageous for studying the role of locally formed estrogen in autoregulating aromatization and in controlling estrogen receptor occupancy, androgen receptor levels, and behavioral expression. Data from these two experimental models reveal a molecular basis for androgen‐estrogen synergism in neuroendocrine tissues and for alterations in androgen sensitivity/responsiveness. These mechanisms are essential components of seasonal reproduction in the test species and may have wider relevance for cyclicity in other vertebrates, including mammal

ISSN:0022-104X    

DOI:10.1002/jez.1402560404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractSeasonal reproduction has emerged as an important topic of investigation which bridges the areas of endocrinology, neurobiology, biological rhythms, and fertility regulation. Among the species in which this topic has been studied, the sheep has proven to be especially useful for investigating the neuroendocrine mechanisms which underlie the seasonal switches in fertility. This is due to a number of attributes. One of these is the large blood volume of sheep which permits extensive sampling for characterizing pulsatile patterns of hormone secretion. Another attribute is the large size of its brain and pituitary gland which facilitates complex neurosurgical procedures such as those required for collecting hypothalamic‐pituitary portal blood for measurement of hypophysiotropic substances. Based on work in sheep, it has become evident that pulsatile secretion of luteinizing hormone (LH) from the anterior pituitary is driven by an episodic discharge of gonadotropin‐releasing hormone (GnRH) from the hypothalamus, and that seasonal reproduction results largely from alterations in the pulsatile pattern of LH release. By using the sheep as a model, it should now be possible to elucidate the neural mechanisms which underlie these seasonal alterations in the reproductive neuroendocrine a

ISSN:0022-104X    

DOI:10.1002/jez.1402560405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractIn the neural system controlling song in passerine birds, gonadal steroid hormones have potent effects on neural growth and differentiation. During ontogeny, sex differences in the secretion of steroid hormones lead to dramatic sex differences in neuron number and structure. In adulthood, sex steroid hormones also cause a significant reorganization of neural circuits. These studies of hormone action have been influential in the development of the field of neuroendocrinology.

ISSN:0022-104X    

DOI:10.1002/jez.1402560406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe caudal neurosecretory peptide urotensin II and its partial structural analog the hypothalamic and gastroenteropancreatic peptide somatostatin can be distinguished by the goby posterior intestine; urotensin II stimulates Na+and Cl−absorption whereas somatostatin is without effect. SandostatinR(Sandoz compound SMS 201‐995) is a partial structural analog of somatostatin, possessing the active core common to both urotensin II and somatostatin but lacking the C‐ and N‐terminal tails which apparently confer recognition in species specificity. SMS 201‐995 mimicked the effects of urotensin II, namely, increased net Cl−absorption and decreased radio‐chloride backflux consistent with the observed increase in transepithelial resistance and the cellular depolarization typical of transport stimulation in this tissue. Speculation on the role of the tails in species‐specific recognition is supported by the nature of amino acid residue substitutions in urotensin II, somatostatin, and SMS 201‐995 and suggests the existence of multiple receptor types for this

ISSN:0022-104X    

DOI:10.1002/jez.1402560407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThis paper presents a summary of experimental studies which utilized the White Leghorn cockerel,Gallus domesticus, as a suitable avian model for a detailed analysis of the mode of action of the seco‐steroid vitamin D. It is now apparent that there exists a complex endocrine system which coordinates the metabolism of the parent vitamin D into a family of over 30 metabolites; the principal metabolites are 1,25(OH)2D3and 24R,25(OH)2D3, which together orchestrate the spectrum of biological responses attributable to vitamin D. Key advances in elucidation of the scope of vitamin D endocrine system include the tissue distribution of both its steroid receptor and its gene‐induced product, a 28,000 dalton calcium binding protein, termed calbindin‐D28k. To date no less than 23 tissues have been found to have specific 1,25(OH)2D3receptors; of these at least 10 were identified in avian studies. Similarly, nine avian tissues have been found to express the vitamin D‐induced calcium binding protein, calbindin‐D28k. These observations collectively demonstrate both the broad scope of the vitamin D endocrine system and the appropriateness of using avians as valid models for vitamin D endocrine research which has applicability and validity for mammals, incl

ISSN:0022-104X    

DOI:10.1002/jez.1402560408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe survival of organisms in a hostile and highly variable environment is dependent upon the proper balance of physiological processes. According to emerging views, homeostasis may be achieved by the coordinated activities of the three major integrative systems: the nervous, endocrine, and immune systems. Although each of these systems is replete with its particular molecules, cells, tissues, and organs, often not seemingly integrated into the whole organism, homeostasis is uncompromised and the three systems function properly. This mini‐review contains the essence of newer approaches which emphasize those which are being developed in our laboratory. Our model is concerned with the regulation of the immune system by the brain in fis

ISSN:0022-104X    

DOI:10.1002/jez.1402560409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe structure of the teleost endocrine pancreas is unique in its tendency to form either a large accumulation of islet tissue (principal islet) or a similar accumulation, surrounded by a rim of exocrine tissue (Brockmann body). This morphological peculiarity constitutes a valuable model for investigation of islet hormones and their interactions. Understanding of the functional and molecular characteristics of the fish pancreas was slowed by the unavailability of purified piscine islet hormones. This obstacle has been overcome recently. Our experiments on the endocrine pancreas of salmon,Oncorhynchussp., which we review here, can serve as an example of the advantages of using a teleost fish in studies of vertebrate pancreatic physiology and biochemistry.

ISSN:0022-104X    

DOI:10.1002/jez.1402560410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractAnimal species that are commonly available for study by the laboratory scientist represent a relatively small portion of the total number of species which exist. For example, domestic and laboratory animals comprise less than 1% of all mammal species; thus the vast majority of the animal diversity is understudied. Although both the need and the interest exist to investigate more and divergent species, access to animals and biological materials is the greatest current impediment to most research programs. As a partial solution to this problem, zoos, parks, and aquaria can serve as resources to provide access to more than 200 mammal species and biological materials which otherwise would not be available. The present report focuses on the potential of these resources in the United States and Canada and presents an overview of the biologic content, the avenues for approaching these resources, as well as the research capacities which are currently present within these institutions. Virtually all zoos, parks, and aquaria support the concept of research. Many have research interests and some already have either their own research programs or share a scientific research program with a research institution located nearby. The most popular research interests in zoological institutions today are behavior and reproductive physiology. Most facilities are willing to share material for other kinds of studies. In general, a notable amount of endocrine data has been produced by zoos, parks, and aquaria over the past 20 years mainly in the field of reproductive endocrinology, and much of this has been collected in collaboration with outside institutions. The potential for research activities to expand is favorable and has perhaps never been better than at the present time.

ISSN:0022-104X    

DOI:10.1002/jez.1402560411

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY