Occurrence and biological activity of estradiol-17β in the intact and ovariectomized Tilapia aurea (Cichlidae, Teleostei)

Yaron, Z.; Terkatin-Shimony, Aviva; Shaham, Y.; Sälzer, H.

doi:10.1016/0016-6480(77)90126-5

Cited by 45 publications

(11 citation statements)

References 14 publications

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“…Treatment with E l was followed by an increase of the plasma calcium but not of protein. The effect of E 2 on these parameters was significant and similar to that reported earlier in this fish (Yaron et al, 1977) (fig. 2a, b).…”

supporting

confidence: 90%

Estrogens and estrogenic effects in Tilapia aurea (Cichlidae, Teleostei)

Terkatin-Shimony¹,

Yaron²

1978

Ann. Biol. anim. Bioch. Biophys.

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Summary. Estradiol (E 2 ) level in plasma of non-breeding female Tilapia aurea, measured by RIA, was 0.33: : :!:: 0.02 ng/mi (mean ± SEM, n = 6). This level is about 10 p. 100 of the level found in breeding females, about 4 times higher than in ovariectomized females and similar to the level found in non-breeding males.Twenty-four hours following a single i. p. injection of 0.5 mg E 2 , the estradiol level in plasma of ovariectomized Tilapia was within the physiological range (0,2-10 ng/mi). This level was maintained for at least 4 days. Comparison of the vitellogenic potency of 3 estrogens in ovariectomized T. aurea shows that estriol was more potent than estradiol, which, in turn, was more potent than estrone. Since E 2 increased in the plasma of estrone-injected fish, it is assumed that estrone was converted to estradiol in the recipient fish.Introduction.

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supporting

confidence: 90%

Estrogens and estrogenic effects in Tilapia aurea (Cichlidae, Teleostei)

Terkatin-Shimony¹,

Yaron²

1978

Ann. Biol. anim. Bioch. Biophys.

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“…During that stage plasma estrogen values began to increase rapidly. These observations agree with the role assigned to estradiol-17(3 in the stimulation of vitellogenin synthesis in the liver (Campbell and Idler, 1976 ;Yaron et al, 1977 ;Terkatin-Shimony and Yaron, 1978 ;Crim and Idler, 1978). The estradiol-17p/estrone ratio studied at the different ovarian stages and as a function of perifusion time indicates that estradiol-17!…”

supporting

confidence: 83%

In vitro effect of a fish gonadotropin on aromatase and 17 β-hydroxysteroid dehydrogenase activities in the ovary of the rainbow trout (Salmo gairdneri Rich.)

Sire¹,

Dépêche²

1981

Reprod. Nutr. Dévelop.

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Summary. Aromatase activity has been studied in the rainbow trout ovary in a perifusion system. During early vitellogenesis, as in other stages of the annual cycle, the ovaries were capable of aromatizing androstenedione and testosterone. Aromatase activity increased from the postovulatory stages to exogenous vitellogenesis.When highly purified salmon glycoprotein maturational gonadotropin was added to the medium (50 ng/ml), the androstenedione/testosterone ratio was reduced by half. This indicates a stimulation of 17p-hydroxysteroid dehydrogenase activity favourizing the formation of testosterone. At a concentration of 50, 150 or 300 ng/ml, the gonadotropin inhibited between 13 and 38 p. 100 of the aromatase enzymatic activity.Introduction.

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“…Estradiol was determined by RIA as detailed in Yaron et al (1977). The sensitivity of the standard curve was 4.1 pg/tube and that of the assay was 48.3 pg/ml for serum samples of 0.8 ml.…”

Section: Determination Of Steroidsmentioning

confidence: 99%

Fluctuations in gonadotropin and ovarian steroids during the annual cycle and spawning of the common carp

Yaron

Levavi-Zermonsky

1986

Fish Physiol Biochem

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The main objective of the paper is to describe the annual changes in hormones associated with reproduction in the female carp under the conditions prevailing in the Israeli fish culture. Fish were sampled monthly throughout 1984; gonadosomatic index (GSI) was calculated and the diameter of ovarian follicles was measured. Gonadotropin (GTH) content in the pituitary and the circulating GTH, estradiol, testosterone and 17α, 20β-dihydroxy-4-pregnen-3-one (17, 20-P) were determined by specific radioimmunoassays. GTH, estradiol and testosterone showed a bimodal annual pattern. The late summer peak was associated with initial vitellogenesis while the peak in spring occurred just before spawning, which took place in April-May. A resting phase in ovarian activity was noted in June and July. The levels of 17, 20-P were very low compared with those occurring during spawning induction. The paper summarizes a previous study by our laboratory on the changes in circulating hormones, as related to oocyte stages, in female carp induced to spawn by a GTH-calibrated pituitary extract. This study associates the short but prominent peak in 17, 20-P with the presence of follicles with maturing oocytes in the ovary. A correlation was found between the percentage of oocytes with eccentric germinal vesicle initially present in ovarian biopsies of females carp and their spawning success after hypophysation. The paper describes simple means to ensure successful induction of spawning in carp by utilizing a calibrated pituitary extract and prior selection of females that would respond to the induction treatment.

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Occurrence and biological activity of estradiol-17β in the intact and ovariectomized Tilapia aurea (Cichlidae, Teleostei)

Cited by 45 publications

References 14 publications

Estrogens and estrogenic effects in Tilapia aurea (Cichlidae, Teleostei)

Estrogens and estrogenic effects in Tilapia aurea (Cichlidae, Teleostei)

In vitro effect of a fish gonadotropin on aromatase and 17 β-hydroxysteroid dehydrogenase activities in the ovary of the rainbow trout (Salmo gairdneri Rich.)

Fluctuations in gonadotropin and ovarian steroids during the annual cycle and spawning of the common carp

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