Sustained hormone release. I. Characteristics of in vitro release of gonadotropin-releasing hormone analogue (GnRH-A) from pellets

Sherwood, Nancy M.; Crim, L.W.; Carolsfeld, Joachim; Walters, Sandra M.

doi:10.1016/0044-8486(88)90088-9

Cited by 87 publications

(25 citation statements)

References 18 publications

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“…Plasma GnRHa was quantified in 5-25 il of nonextracted, heparinized plasma by a [1 25 ]iodine RIA developed by Sherwood et al [30]. The sensitivity of the assay is 50 pg/ml; the intraassay coefficient of variation (CV) was 8.9% and the interassay CV was 9.5% (n = 3).…”

Section: Hormonal Measurementsmentioning

confidence: 99%

Changes in Plasma Gonadotropin II and Sex Steroid Hormones, and Sperm Production of Striped Bass after Treatment with Controlled-Release Gonadotropin-Releasing Hormone Agonist-Delivery Systems1

Mylonas

Scott

Vermeirssen

et al. 1997

Biology of Reproduction

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Spermiating striped bass, a perciform fish, were treated with two controlled-release gonadotropin-releasing hormone agonist (GnRHa)-delivery systems, and the resulting changes in plasma gonadotropin II (GTH II), testosterone (T), 11-ketotestosterone (11-KT), 17,20beta-dihydroxy-4-pregnen-3-one (17,20beta-P), and 17,20beta,21-trihydroxy-4-pregnen-3-one (17,20beta,21-P) were correlated with changes in milt production and sperm density. GnRHa-delivery systems induced a sustained elevation of plasma GnRHa and GTH II for 14 days. Plasma T levels were unchanged after GnRHa treatment, while 11-KT levels increased significantly. Plasma 17,20beta-P also increased after GnRHa treatment and remained elevated compared to levels in controls, while plasma 17,20beta,21-P levels were unaffected. Both GnRHa-delivery systems induced many-fold increases in total expressible milt, lasting throughout the 14 days of the study. Sperm density decreased 2 days after GnRHa treatment, with a subsequent increase by Day 7. This study demonstrates that GnRHa-delivery systems induce a sustained elevation of plasma GTH II levels in striped bass, resulting in a long-term enhancement of milt production. The endocrine changes observed suggest that 11-KT and 17,20beta-P, but not 17,20beta,21 -P, are mediating the effects of GTH II on spermiation.

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Section: Hormonal Measurementsmentioning

confidence: 99%

Changes in Plasma Gonadotropin II and Sex Steroid Hormones, and Sperm Production of Striped Bass after Treatment with Controlled-Release Gonadotropin-Releasing Hormone Agonist-Delivery Systems1

Mylonas

Scott

Vermeirssen

et al. 1997

Biology of Reproduction

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“…This suggests that the optimal effective dose of GnRHa varies between species and that the degree of maturity and GnRHa pellet matrix are important for successful ovulation (Sherwood et al 1988). Similar to greenback flounder, GnRHa (200 lg, ini) pellet implantation resulted in fewer ovulations and a smaller number of eggs ovulated compared to treatment with 100 lg of GnRHa (ini) and pellet implantation in this study (Poortenaar and Pankhurst 2000).…”

Section: Discussionmentioning

confidence: 62%

Effect of exogenous hormones on ovulation and gonadal steroid plasma levels in starry flounder, Platichthys stellatus

Lim

2016

Aquacult Int

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The present study was designed to examine the potential for inducing ovulation in starry flounder (Platichthys stellatus) using gonadotropin-releasing hormone analog (GnRHa) and human chorionic gonadotropin (hCG) to assess whether starry flounder are differentially responsive to GnRHa and hCG. Female starry flounder were injected or implanted with different doses of hCG or GnRHa pellets to examine their ovulationinducing potential and effects on plasma levels of testosterone (T), 17b-estradiol (E2), and 17,20b-dihydroxy-4-pregnen-3-one (17,20bP). Blood samples were collected for up to 10 or 25 days post-injection or post-implantation in two separate experiments designed to mimic the early and middle stages of spawning, respectively. Fish treated with the GnRHa pellets (100 lg) showed a significant increase in the total number of stripped eggs relative to the controls. GnRHa administration had no effect on the floating rate or fertilization rate of ovulated eggs in the both experiments, whereas hCG injection affected both of these rates. Plasma T levels were not significantly different between the exogenous hormonetreated and control fish. In contrast, the plasma E2 level was elevated in those fish treated with GnRHa, regardless of injection or implantation, and was accompanied by increased numbers of stripped eggs in both experiments. Treatment with GnRHa resulted in higher 17,20bP levels compared to the controls, and there was a positive relationship between elevated plasma 17,20bP and an increase in ovulated eggs in response to GnRHa treatment. The implantation of starry flounder with GnRHa-containing pellets was effective at inducing sustained ovulation compared to hCG treatment.

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“…Therefore, MO 2 was recorded 2-11 days after implantation. This time period corresponds with the surge of hormones from slow-release cholesterol pellets (Sherwood et al, 1988) and is within the period that GH is elevated in the blood stream (Boeuf et al, 1994). Implantation caused no signs of distress and fish recovered rapidly from anaesthesia.…”

mentioning

confidence: 83%

Evidence that growth hormone‐induced elevation in routine metabolism of juvenile Atlantic salmon is a result of increased spontaneous activity

Herbert

Armstrong

Björnsson

2001

Journal of Fish Biology

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Sustained hormone release. I. Characteristics of in vitro release of gonadotropin-releasing hormone analogue (GnRH-A) from pellets

Cited by 87 publications

References 18 publications

Changes in Plasma Gonadotropin II and Sex Steroid Hormones, and Sperm Production of Striped Bass after Treatment with Controlled-Release Gonadotropin-Releasing Hormone Agonist-Delivery Systems1

Changes in Plasma Gonadotropin II and Sex Steroid Hormones, and Sperm Production of Striped Bass after Treatment with Controlled-Release Gonadotropin-Releasing Hormone Agonist-Delivery Systems1

Effect of exogenous hormones on ovulation and gonadal steroid plasma levels in starry flounder, Platichthys stellatus

Evidence that growth hormone‐induced elevation in routine metabolism of juvenile Atlantic salmon is a result of increased spontaneous activity

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