Temporal responsiveness of the ovary of goldfish to gonatropin

Peter, Richard; Paulencu, C. R.; Breton, Bernard

doi:10.1080/09291018209359781

Cited by 20 publications

(4 citation statements)

References 21 publications

(27 reference statements)

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“…Perhaps this low level of reaction indicates that sea bass ovaries have a temporal variation in reponsiveness to the hormone injection. Both in vivo and in vitro evidence suggest that the responsiveness of teleost gonads to hormone stimulation varied at certain times during the day (DE VLAMING and VODICNIK 1977;Kuo and WATANABE 1978;PETER et al 1982). The present results seem to support this view; however, more tests are needed to further elucidate this matter in sea bass.…”

Section: Discussionsupporting

confidence: 58%

Spawning response latency and egg production capacity of LHRHa-injected mature female sea bass, Lates calcarifer Bloch

Garcia¹

1990

J Appl Ichthyol

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Mature female sea bass (Lates calcarifer Bloch) were injected once intramuscularly with 20 pg luteinizing hormone-releasing hormone analogue (D-Ala6, Pro'-LHRH-ethylamide) per kg body weight (BW) at different times of the day. Following hormone injection, the incidence of initial spawning and the number of eggs spawned by each fish were recorded. Saline-injected fish did not spawn. Fish spawned at dawn or 33.7-40 h after an LHRHa injection at either 11.00 h or 17.00 h. When LHRHa was administered at 23.00 h or 05.00 h, sea bass spawned during the day or at 38-47.3 h post-injection. Mean egg production levels of 26.8-34.4 x lo4 per kg BWwere higher for fish which spawned at dawn. Low mean egg production levels (6.2-19.9 x lo4 eggs per kg BW) were observed when LHRHa-injected fish spawned during the day. These results demonstrate that the time of initial occurrence of spawning varied with the time of day that LHRHa was administered and that the number of eggs shed was influenced by the time of day that hormone-induced sea bass spawned. Zusammenfassung Verzogerung der Ablaichreaktion und Kapazitat der Eiproduktion von LHRHa-injizierten regenSeebarschweibchen (Lates calcarifer Bloch) Reife Weibchen des Seebarsches Lates calcarifer Bloch wurden einmalig intramuskular mit 20 pg des Juteinizing hormone-releasing hormone" Analogons (D-Ala6, Pro9-LHRH-ethylamid) pro kg Korergewicht zu verschiedenenTa eszeiten injiziert. Nach der Injektion des Hormons wurde die Haufig-Eeit der erzielten Laichreife u n j die Zahl der abgelaichten Eier pro Fisch erfaRt. Salz-injezierte Kontrollfische laichten nicht. Behandelte Fische laichten 34 bis 40 h nach der LHRHa-Behandlung entweder um 11.00 Uhr oder urn 17.00 Uhr. Wenn die LHRHa-Dosis urn 23.00 Uhr oder 05.00 Uhr verabfolgt wurde, laichten die Seebarsche wihrend des Tages oder 38-47 Stunden spater. Die mittlere Zahl der abgelaichten Eier betrug 26,8-34,4 x lo4 pro kg Fisch und war stets hoher fiir Fische die zur D h m erungszeit laichten. Niedrige mittlere Eizahlen (6,2-19,9 x lo4 Eier pro kg Korper ewicht) wurden enielt wenn die behandelten Fische am Tage laichten. Diese Ergebnisse machen ieutlich, dai3 das Erstlaichen mit der Tageszeit der LHRH-Injection variiert und das die Zahl der Eier von der Tageszeit zu der gelaicht wird, beeinflufit ist. RisumC Retardement du frai et capaciti de production d' oeufi des femelles matures de ban-amundi (Lates calcarzfer Bloch) injecteespar un analogue du facreur de liberation de I'honnone luteinisanteDes femelles matures du barramundi (Lates calcarifer Bloch) ont P t i traitees par une injection intramusculaire de 20 pg ar kg de poids de Poisson d'un analogue du facteur de liberation de I' hormone lutiinisante (D-Afa6, Pro9-LHRH-eth lamide) ii differentes heures de la journie. Aprh I'injection, I'incidence initiale du frai et le nombre Joeufs frayis par poissons ont C t i misuris. Les oksons injectis injection de LHRHa ii 11.00 ou 17.00 heures. Quand le LHRAa a it6 administri h 23.00 ou 5.00 heures, les barramundis frayaient pendant la journie ...

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Section: Discussionsupporting

confidence: 58%

Spawning response latency and egg production capacity of LHRHa-injected mature female sea bass, Lates calcarifer Bloch

Garcia¹

1990

J Appl Ichthyol

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“…The circadian rhythm in GtH levels ovulatory period might be relat allel rhythm in the sensitivity of to GtH. A daily cycle in the respo of the ovary (indicated by its growth rate) to gonadotropin treatment has been observed in Notemigunus crysoleusas (de Vlaming and Vodicnik, 1977) and in the goldfish (Peter et al, 1982). The last study showed that under some e~virQ~~~~ta1 conditions, there was a synchronization between the temporal changes in ovarian se sitivity to GtH and the daily cycle of Gt levels in the plasma.…”

Section: Discussionmentioning

confidence: 95%

Short-term profiles of plasma gonadotropin and 17α-hydroxy, 20β-dihydroprogesterone levels in the female rainbow trout at the periovulatory period

Zohar¹,

Breton²,

Fostier³

1986

General and Comparative Endocrinology

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Individual free-swimming female rainbow trout in which oocytes underwent final stages of germinal vesicle migration, maturation, or ovulation were bled via a dorsal-aortic catheter at frequencies of once every 1, 3, or 4 hr over periods of 9 to 36 hr. Gonadotropin (GtH) and 17 alpha-hydroxy,20 beta-dihydroprogesterone (17 alpha,20 beta-OHP) levels were measured in the plasma samples. GtH levels were elevated and showed wide and progressive daily variations. A high degree of synchronization appeared among the GtH profiles of individual fish. Two distinct daily GtH surges were observed, one at early photophase and the other during the mid-scotophase. The onset of the GtH increases was closely related to the beginning of the photophase and the scotophase, respectively. In females undergoing oocyte maturation or in ovulated females, 17 alpha,20 beta-OHP levels were increasing or high, showing progressive daily fluctuations that were either synchronized with the GtH changes or somewhat phase-shifted in relation to them. These data are discussed in relation to the seasonal changes in the short-term profiles of reproductive hormones in the trout.

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“…In castrated and sham-operated catfish, plasma GTH levels were determined at various time intervals following intraperitoneal injections (0.05 tLg/g body weight) with [Dser(t-Bu) 6 , Pro 9 -NEt]-GnRH (Buserelin), a superactive GnRH agonist in catfish (De Leeuw et al 1988b). Serum GTH levels in goldfish and plasma GTH levels in catfish were measured, using radioimmunoassays (RIA) as described previously by Peter et al (1983) and Goos et al (1986), respectively. Androstenedione was measured by RIA (carried out by Prof. Dr. J.H.H.…”

Section: Determination Of Gth and Steroidsmentioning

confidence: 99%

Pituitary gonadotropin-releasing hormone (GnRH) receptor activity in goldfish and catfish: seasonal and gonadal effects

Habibi

et al. 1989

Fish Physiol Biochem

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The goldfish pituitary contains two classes of gonadotropin-releasing hormone (GnRH) binding sites, a high affinity/low capacity site and a low affinity/high capacity site (Habibiet al. 1987a), whereas the catfish pituitary contains a single class of high affinity GnRH binding sites (De Leeuwet al. 1988a). Seasonal variations in pituitary GnRH receptor binding parameters, and the effect of castration on pituitary GnRH receptor binding were investigated in goldfish and catfish, respectively. In goldfish, GnRH receptors undergo seasonal variation with the highest pituitary content of both high and low affinity sites occurring during the late stages of gonadal recrudescence. The observed changes in pituitary GnRH receptor content correlate closely with responsiveness to a GnRH agonistin vivo in terms of serum gonadotropin (GTH) levels. In catfish, castration results in a two-fold increase in pituitary GnRH receptor content, which can be reversed by concomitant treatment with androstenedione, but not by the non-aromatizable androgen 11β-hydroxyandrostenedione; changes observed in GnRH receptor content correlate with variations in serum GTH levels and responsiveness to a GnRH agonist. In summary, the present study provides a clear evidence for seasonal variation in pituitary GnRH receptor activity in goldfish, and demonstrates a gonadal feedback mechanism regulating GnRH receptor activity in the catfish pituitary.

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Temporal responsiveness of the ovary of goldfish to gonatropin

Cited by 20 publications

References 21 publications

Spawning response latency and egg production capacity of LHRHa-injected mature female sea bass, Lates calcarifer Bloch

Spawning response latency and egg production capacity of LHRHa-injected mature female sea bass, Lates calcarifer Bloch

Short-term profiles of plasma gonadotropin and 17α-hydroxy, 20β-dihydroprogesterone levels in the female rainbow trout at the periovulatory period

Pituitary gonadotropin-releasing hormone (GnRH) receptor activity in goldfish and catfish: seasonal and gonadal effects

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