摘要:

AbstractFour Zebu and four Simmental oxen were submitted to continuous and to graded draught work. Venous blood samples were taken before, during, and after exercise at intervals of 2–5 min. Anaerobic threshold was reached at a draught power of 1.6 ± 0.06 kW for Zebu and 0.7 ± 0.07 kW for Simmental. Corresponding plasma lactate concentrations were 1.7 ± 0.2 mmol/liter and 1.6 ± 0.3 mmol/liter, respectively. Partial pressure of oxygen (pvO2), carbon dioxide (pvCO2), and plasma free fatty acids (FFA) during and after work differed between breeds (P ∼ .001) and individuals (P ∼ .05). After work, an up to 8‐fold increase in FFA was found. Highest plasma lactate concentrations during continuous maximal draught were 3.75 ± 1.76 (Zebu) and 6.01 ± 0.88 mmol/liter (Simmental). Acid‐base‐state during and after exhaustive work remained stable. Heart rate in both breeds did not exceed 190 min−1. It is concluded that 1) even during heavy draught work, anaerobic energy formation plays a minor role for cattle, 2) fatigue in working oxen may be related to cardiovascular limitations, and 3) the physical fitness of European beef‐breed oxen is lower compared to multipurpose African Zebu oxen.

ISSN:0022-104X    

DOI:10.1002/jez.1402660402

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

年代:1993

数据来源: WILEY

摘要:

AbstractTwo different lipoproteins, lipoprotein I and very high density lipoprotein (VHDL), were isolated from the male hemolymphs of freshwater prawn, mitten crab, and striped stone crab by a different density gradient ultracentrifugation. Lipoprotein II as well as lipoprotein I and VHDL was further found in the female hemolymphs of these crustacea. Lipoprotein II seemed to be a vitellogenin and spawned kuruma prawn without eggs lacked lipoprotein II in their hemolymph. The densities of lipoprotein I varied between 1.12 and 1.18 g/ml reflecting the difference of protein‐lipid ratio. In contrast lipoprotein II and VHDL had approximately constant densities of 1.19—1.21 g/ml and 1.26—1.27 g/ml, respectively. Lipoprotein I, lipoprotein II, and VHDL isolated from the crustacean hemolymph contained phospholipid as a predominant lipid component. Crustacean lipoprotein was divided into the freshwater type and the seawater type. Freshwater prawn and mitten crab classified into the freshwater type tended to have high protein concentrations in lipoprotein I and VHDL. In contrast both lipoprotein I and VHDL protein concentrations from kuruma prawn and striped stone crab, which were classified into the seawater type, were much lower than those from the freshwater type. Lipoprotein I from freshwater prawn and mitten crab had two major apolipoproteins with apparent molecular weights of 230,000 and 100,000, and 340,000 and 100,000, respectively, while lipoprotein I from kuruma prawn and striped stone crab consisted of three major apolipoproteins (molecular weights 180,000, 100,000, and 80,000). VHDL found for the first time in crustacea probably plays an important role in lipid transfer reaction between lipoproteins. © 1993 Wiley‐L

ISSN:0022-104X    

DOI:10.1002/jez.1402660403

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

年代:1993

数据来源: WILEY

摘要:

AbstractLeydig cells were enzymatically separated from the seminiferous tubules and were then purified by isoosmotic Percoll gradient centrifugation so that steroidogenic activity in the two sites could be measured separately. After purification, the cells in fractions 29–31 were identified as Leydig cells since these tested positively for 3β hydroxysteroid dehydrogenase activity (3β HSD), had steroidogenic ultrastructural features (smooth endoplasmic reticulum), and were capable of synthesizing testosterone (T) in vitro. The rest of the fractions tested negatively for the 3β HSD activity and were incapable of synthesizing detectable amounts of T. Sertoli cells from seminiferous tubules also showed the above steroidogenic properties. The T concentration of intratubular origin (Sertoli cells) was low prior to spermatogenesis but began to rise at the onset of the spermatogenic phase (late May to early June). The level of Sertoli T increased steadily during the summer. In late August to early September intratubular T reached a peak that coincided with spermiation and maximal testicular development. Leydig cells (interstitial origin) were more active prior to spermatogenesis, producing large amounts of T at a time of minimal testicular mass. The sharply rising T concentrations peaked in May or early June (mating period). After the onset of spermatogenesis, T of interstitial origin began to drop until early August to early September when, like T of intratubular origin, it peaked in synchrony with spermiation and maximal testes development. During September the testes regressed rapidly and T from both sources declined significantly. Throughout the cycle the Leydig cells appeared to be the major site of testosterone synthesis. © 1993 Wiley‐Li

ISSN:0022-104X    

DOI:10.1002/jez.1402660404

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

年代:1993

数据来源: WILEY

摘要:

AbstractChickenII‐(cII‐) and salmon (s‐) GnRH levels have been measured in the male frogRana esculentaduring the annual cycle. The presence of pituitary binding activity for both peptides and plasma androgen levels has been investigated in order to give insight into the significance of the dual control exerted by the GnRH forms present in theR. esculentabrain. ChickenII‐ and s‐GnRHs showed high values during the spring‐summer period. Conversely, while cII‐GnRH peaked in February, s‐GnRH declined slowly from February until May. Plasma androgen levels increased as the peptides decreased during the autumn‐winter period. Still high androgen levels (but significantly lower as compared with winter concentrations) were found during spring. Using iodinated cII‐GnRH, GnRH binding sites were detected in pituitary preparations when the corresponding peptide concentration decreased in the brain. On the contrary, no binding sites were found using labeled s‐GnRH. Our results indicate that cII‐GnRH has a hypophysiotropic activity, while the role of s‐GnRH needs to be further investigate

ISSN:0022-104X    

DOI:10.1002/jez.1402660405

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

年代:1993

数据来源: WILEY

摘要:

AbstractInsulin stimulation of the glucose uptake by the thyroid gland of the turtle (Chrysemys dorbigni) has been previously reported. The aim of the present study was to examine the influence of different temperatures (6, 25, or 36°C) on this effect. Insulin‐stimulated glucose uptake was evident when turtles were acclimated for 15 days at 25° or 36°C, and their glands studied at the respective temperatures. In glands from turtles acclimated at 6°C, this effect was only seen when the preincubation and incubation time was extended from 60 to 300 min. The findings show that in this ectotherm species (1) the insulin effect is temperature dependent, and (2) can be expressed at very low temperature. © 1993 Wiley‐L

ISSN:0022-104X    

DOI:10.1002/jez.1402660406

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe effects of porcine growth hormone (pGH) or ovine prolactin (oPRL) alone and in combination with triiodothyronine (T3) on renal PRL receptors were determined in both pre‐ and post‐metamorphic tiger salamanders(Ambystoma tigrinum).The protein hormones were given at a dose of 1.0 μg/gm body weight/day and the T3was given at 10.0 ng/gm body weight/day. The duration of treatment was 7 days. Effects on growth, and plasma thyroid hormone levels were also determined. Ovine PRL increased growth in both larvae and adults and reversed metamorphic changes. Administration of T3increased the plasma T3concentration, as measured by radioimmunoassay, and when given alone caused weight loss at both stages. The GH decreased plasma T4and increased plasma T3concentrations, indicating that it caused an increase in T4deiodination. In adults the renal PRL receptor affinity of 2.9 ± 0.7 × 1010L/mol and capacity of 160 ± 22 fmol/mg protein were higher than the corresponding values of 1.8 ± 0.3 × 1010L/mol and 29.2 ± 3.8 fmol/mg in larvae. In adults only, there is an additional low‐affinity, high capacity PRL binding site. The oPRL treatment decreased the binding capacity to 33.2 ± 1.2 and 5.9 ± 4.9 fmol/mg in adults and larvae, respectively. By contrast, pGH increased the capacities to 249 ± 18 and 62.1 ± 6.8 fmol/mg in adults and larvae, respectively. Treatment with T3alone doubled the oPRL binding capacity to 58.3 ± 4.7 fmol/mg in larvae, but there was no effect in adults. In both developmental stages the effects of oPRL and pGH on the receptors were not changed by the simultaneous T3treatment. Porcine GH treatment both with and without T3reduced the PRL binding affinity, but the effect was significant only in larvae. The effect of oPRL on binding affinities could not be determined, because the binding capacity was so low. In adults the low‐affinity site was detectable in all treatment groups, but none of the treatments caused the appearance of the low‐affinity binding site in larval kidneys, even when they increased the binding capacity to adult levels (T3, pGH, or both together). It therefore seems likely that some other factors are involved in the development of the adult binding pattern. The increased oPRL binding capacity caused by pGH in larvae and adults may be secondary to its effect on serum T3levels. However, the reduction in Kavalues in the larvae may be caused by GH itself, possibly due to an increase in the number of the low‐affinity sites.

ISSN:0022-104X    

DOI:10.1002/jez.1402660407

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

年代:1993

数据来源: WILEY

摘要:

AbstractPrevious in vivo and in vitro studies indicate that insulin is required in adult newt forelimb regeneration. The objectives of the current study were 1) to detect insulin receptors in the liver (a classical target organ for insulin) and once verified, detection of insulin receptors in the adult newt forelimb regenerate; and 2) to determine whether locally implanting insulin antibody‐soaked hydrolyzed polyacrylamide beads (hypa beads) into a regenerating forelimb blastema would affect its growth and/or differentiation. The results show that insulin receptors are detectable in the plasma membranes of newt liver and forelimb regenerates. Radioiodinated bovine insulin binding is time‐dependent and specific; unlabeled bovine insulin competes with labeled insulin for binding to NLPM more effectively than does insulin‐like growth factor‐I, guinea pig insulin, and glucagon. The newt hepatic insulin receptor binds insulin with high affinity (1.1 nM−1) and low capacity (63 ± 8 fmoles/mg). The size of the alpha subunit of the newt insulin receptor is 130 kDA and that of the beta subunit is 95 kDa. The β subunits undergo insulin‐stimulated phosphorylation in response to insulin. An autoantibody against the human insulin receptor recognizes the newt receptor protein. Insulin receptors are also detectable in 15 and 20 day newt forelimb regenerates. Specific immunogold labelling of the receptor‐bound antibody appears to be restricted to the cellular processes of the regenerate. Implanting hypa beads soaked with purified insulin antibody into regenerating adult newt forelimbs results in abnormal growth and differentiation of the regenerates, confirming that insulin plays an essential role in adult newt forelimb regeneration. © 1993

ISSN:0022-104X    

DOI:10.1002/jez.1402660408

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

年代:1993

数据来源: WILEY

摘要:

AbstractMale hybrids produced from reciprocal crosses betweenOryzias latipesandO. curvinotusare sterile, whereas females do lay eggs. Fertilized by the sperm of one of the parental species, such eggs develop into triploid males and females. We examined allozyme patterns of triploids that developed from the eggs fertilized by sperms of non‐parental strains ofO. latipesor a closely related species,O. luzonensis.Expression of three allelic products in triploid offsprings indicated unreduced diploidy of the eggs produced by the hybrid females.In order to test the clonality of the diploid eggs produced by the hybrid females, we examined the progeny of hybrid females for their immunological clonality and DNA content. Progeny of a hybrid female crossed with a male of an inbred strain ofO. latipeswas demonstrated to belong to a single immunological clone. Differences in frequency of hypotriploidy and mosaicism were observed between strains ofO. latipesthat produced hybrid females.BecauseO. latipesis a fish that is used widely as a model organism in experimental biology, the hybrid females that produce unreduced diploid eggs provide a unique model with which to examine the underlying causes of polyploidy and clonal reproduction in vertebrates. © 1993 Wiley‐Liss,

ISSN:0022-104X    

DOI:10.1002/jez.1402660409

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

年代:1993

数据来源: WILEY

摘要:

AbstractHemocytes were fractionated by centrifugation on a discontinuous Percoll density gradient from the hemolymph ofPhallusia mamillata.Results obtained from microcultures of the fractionated hemocytes, sugar‐inhibition experiments, SDS‐PAGE, and immunoblotting indicate that “compartment cells” release cellular‐type (CL) lectins that are specific for α‐lactose and lactulose. The released lectins have the same properties as the CL lectins that were previously isolated from sonicated unfractionated hemocytes, but they differ in terms of some molecular and immunological properties from the lectins (SL) purified from the serum. SLs were never found in the supernatants from microcultures of the fractionated hemocytes. © 1993 Wi

ISSN:0022-104X    

DOI:10.1002/jez.1402660410

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

年代:1993

数据来源: WILEY

摘要:

AbstractIn the golden hamster, high‐molecular‐weight glycoproteins are secreted by the epithelial cells of the oviduct. The present study was designed to investigate the possibility that the rat oviduct produces specific glycoproteins similar to the oviductal glycoproteins (GHOGPs) of the golden hamster. Oviductal extracts and oviductal fluids obtained from ovulatory rats were analysed by immunoblotting for the presence of glycoproteins that cross‐react with a monoclonal antibody (MAb) against GHOGPs. The MAb immunoreacted with a broad band of proteins with a range of molecular weights (MWs) of above 330 kD in oviductal extracts or oviductal fluid after fractionation by electrophoresis under reducing conditions, but these proteins were not present in serum and uterine flushings. An immunohistochemical study demonstrated that the MAb bound strongly to the epithelial cells of the oviduct and, to a lesser extent, to those of the large intestine. Weak reactions were also observed with some other tissues. However, similar material of high MW was not detected in extracts of tissues from the other organs, suggesting that the glycoprotein of high MW that reacted with the MAb is specific for the oviduct. Ultrastructural immunocytochemistry revealed that the MAb reacted specifically with putative secretory granules of nonciliated cells in the oviductal epithelium. These results indicate that the oviductal epithelial cells of the rat produce a specific glycoprotein that is immunologically similar to GHOGPs. © 1993 Wiley‐L

ISSN:0022-104X    

DOI:10.1002/jez.1402660411

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

年代:1993

数据来源: WILEY