摘要:

AbstractWe have previously shown that fetal mouse ovaries develop testicular structures after transplantation into adult male mice. The mechanisms of gonadal sex reversal is poorly understood. In the present study, we examined how a host environment is involved in the induction of testicular development in ovarian grafts. Fetal ovaries on the twelfth day of gestation were microencapsulated with semipermeable membranes, transplanted beneath the kidney capsules of adult male mice, and fixed for histological examinations between the sixteenth and twenty‐second day after transplantation. Fifteen of forty‐seven ovarian grafts were found to be completely enclosed in microcapsules, whereas the microcapsule membranes of other grafts were partly broken or had been lost. These differences of microencapsulation conditions made it possible to study the role of host factors in gonadal sex reversal. All ovarian grafts surrounded by microcapsule membranes developed ovarian structures. In contrast, most ovarian grafts which had lost the microcapsules developed testicular structures in addition to ovarian structures. When ovarian grafts were partially enclosed in microcapsule membranes, testicular structures developed only in the area in contact with the host kidney. These results suggest that direct interaction between the ovarian graft and cells or large macromolecules from the host is involved in the development of testicular structures in ovarian gra

ISSN:0022-104X    

DOI:10.1002/jez.1402410112

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

年代:1987

数据来源: WILEY

摘要:

AbstractThe effects of forskolin (FK) on in vitro oocyte maturation and production of steroids were examined inOryzias latipes. When oocytes within preovulatory follicles were preincubated in the presence of FK for 2–10 hr, they matured normally after additional incubation for 10–20 hr in plain culture medium. Naked (follicle cell‐free) oocytes did not mature under these conditions. FK stimulated dose‐dependent production of steroids (estradiol‐17β, E2, and 17α,20β‐dihydroxy‐4‐pregnen‐3‐one, 17α,20β‐diOHprog) and cAMP in follicle (granulosa) cells. On the other hand, exposure to FK within 2 hr after 17α,20β‐diOH prog stimulation caused reversible inhibition of gonadotropin (PMS)‐ or 17α,20β‐diOH prog‐induced maturation of the intrafollicular oocytes in vitro. FK also significantly inhibited the 17α,20β‐diOHprog‐induced maturation of naked oocytes, suggesting the existence of adenylate cyclase in fish oocytes. These data indicate that inOryzias latipes, FK induces oocyte maturation by stimulating follicular production of maturation‐inducing steroid (MIS), probably 17α,20β‐diOH prog, via an increase in cAMP, and that it may inhibit oocyte maturation by increasing ooplasmic cAMP and some inhibitory interaction between the granulosa cells

ISSN:0022-104X    

DOI:10.1002/jez.1402410113

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

年代:1987

数据来源: WILEY

摘要:

AbstractBaboon serum samples were resolved by starch gel electrophoresis and polyacrylamide gradient gel electrophoresis and stained with naphthol substrates for esterase activity. An esterase that hydrolyzed α‐naphtyl butyrate in preference to α‐naphthyl acetate was found in very high activities in some individuals but not others. It migrated just cathodal of the albumin band in starch gels. In polyacrylamide gradient gels, it co‐migrated with albumin and had an apparent molecular weight of approximately 65,000 daltons. Electrophoretic analysis by gel electrophoresis of random serum samples from male and female baboons indicated that this esterase was present only in the sera of pregnant baboons. Further investigation of serial samples collected from carefully monitored baboons confirmed that the amount of activity of this esterase was correlated with stage of pregnancy. Therefore, it was named pregnancy esterase (PE). PE was detectable by gel electrophoresis and chromogenic staining techniques as early as day 30 of pregnancy; its activity gradually increased with progressive pregnancy and reached maximum activity near full term (182 days). Soon after parturition, the activity of PE decreased rapidly and was not detected in maternal sera by day 14 postpartum. No evidence of PE was detected in sera of pregnant

ISSN:0022-104X    

DOI:10.1002/jez.1402410114

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

年代:1987

数据来源: WILEY

摘要:

AbstractSperm surface changes occurring in the reptile Wolffian duct have been explored with particular references to the snake,Natrix fasciata. In the snake Wolffian duct there are several proteins not present in serum, the pattern of which changes in concert with the seasonal testicular cycle. Whereas testicular spermatozoa did not bind antibody to duct secretions, all Wolffian duct spermatozoa did so over both head and tail, according to immunofluorescence patterns. Thus, on entering the Wolffian duct, the entire surface ofN. fasciataspermatozoa acquires one of more of the duct's secretory components.As indicated by immunofluorescence, immunoelectrophoresis, and immunodiffusion, epitopes on at least some molecules that bind to spermatozoa or that remain free in the duct fluid are shared with those in otherNatrixspecies, but not in more distant reptiles (turtle, anole lizard), nor chicken, rat, or rabbit. In regard to glycoproteins, one prominent con A‐reactive band was present in polyacrylamide gel electrophoresis (PAGE) of snake fluid and more were evident in fluid collected from the turtle duct. However, such lectin‐reactive elements did not bind to spermatozoa as judged by an absence of any change in snake, turtle and lizard sperm lectin‐binding patterns in passing from the testis into and through the Wolffian duct.In all, evidence from these and other species studied begins to suggest that the nature of the post‐testicular sperm surface modification displayed in most vertebrates that fertilize internally may differ in sub‐therian and therian groups, respectively. There appears to be a relative emphasis on glycosyl‐rich surface elements in the latter. The possible significance of these changes for sperm function in the different groups is discussed briefly in terms of sperm survival/storage, as well as capacitation and sperm binding

ISSN:0022-104X    

DOI:10.1002/jez.1402410115

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

年代:1987

数据来源: WILEY

摘要:

AbstractActivities of eight enzymes were measured in the sonic muscle of the gulf toadfish,Opsanus beta, to determine the metabolic poise of this unique tissue and to evaluate potential sex related differences in metabolism. In contrast to a prior study (Pennypacker et al., '85, J. Exp. Zool.,239:259–264), we observed substantial activities of M4‐lactate dehydrogenase, 333 to 482 units/g wet sonic muscle weight. This observation and the presence of high activities of other enzymes of glycolytic and anaerobic metabolism (pyruvate kinase and creatine phosphokinase) lead us to conclude that this tissue has high anaerobic capacity. Also in contrast to the observations of Pennypacker et al. ('85), we found that the activities of some enzymes indicative of aerobic metabolism are relatively low. For example, the activities of citrate synthase found in sonic muscle (1.5 to 2.7 units/g) are only slightly higher than values obtained for toadfish white skeletal muscle (1.2 units/g). The discrepancies between the results obtained by the two studies appear to be methodological ones. Lastly, significant differences in enzyme activities between males and females were observed for lactate dehydrogenase, malate dehydrogenase, and citrate synthase, and possible explantions for these differences are discus

ISSN:0022-104X    

DOI:10.1002/jez.1402410116

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

年代:1987

数据来源: WILEY

摘要:

AbstractActivities of all the enzymes of ornithine‐urea (o‐u) cycle and uricolytic pathway were assayed in different tissues of a freshwater air‐breathing teleost,Heteropneustes fossilis. High activity of all o‐u cycle enzymes as observed in the liver and kidney, were comparable to those of actively ureogenic fishes and amphibians. All the three enzymes of uricolytic pathway were found only in liver tissue. These observations strengthen an earlier suggestion made that active ureogenesis did exist in some freshwater teleosts such asH. fossilis. Presence of an active o‐u cycle inH. fossilisindicates that this fish is either relatively primitive to the purely aquatic freshwater teleosts retaining the ancestral character of a functional o‐u cycle or the genes for the synthesis of o‐u cycle enzymes might have been derepressed as a secondary modification for its adaptation to temporary dehydration or hyper‐ammo

ISSN:0022-104X    

DOI:10.1002/jez.1402410117

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

年代:1987

数据来源: WILEY

摘要:

AbstractThe sex of leopard geckoes is determined by incubation temperature. This study identified their temperature‐sensitive period of sex determination by incubating embryos at a male‐producing temperature (32°C) and a female‐producing temperature (26°C) for various intervals of development and comparing the sex ratios from the different experiments. Eggs incubated at 26° for 14 days (to stage 32) could still develop as either sex, but eggs incubated 30 days (through stage 34) necessarily became female; incubation at 32° did not guarantee male development until 20 days of incubation (to stage 37). The temperature‐sensitive period of irreversible sex determination therefore lies between stages 32–37 and occupies much of the first half of development. The temperature‐sensitive period in geckoes is similar to those in turtles and alligators, which are only distantly related to geckoes, but the reasons for these similarit

ISSN:0022-104X    

DOI:10.1002/jez.1402410118

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

年代:1987

数据来源: WILEY

ISSN:0022-104X    

DOI:10.1002/jez.1402410119

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

年代:1987

数据来源: WILEY

ISSN:0022-104X    

DOI:10.1002/jez.1402410101

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

年代:1987

数据来源: WILEY