Seasonal changes of responses to gonadotropin-releasing hormone analog in expression of growth hormone/prolactin/somatolactin genes in the pituitary of masu salmon

Bhandari, Ramji Kumar; Taniyama, Shinya; Kitahashi, Takashi; Ando, Hironori; Yamauchi, Kazuyo; Zohar, Yonathan; Ueda, Hiroshi; Urano, Akihisa

doi:10.1016/s0016-6480(02)00536-1

Cited by 63 publications

(38 citation statements)

References 33 publications

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“…In this species sGnRH at a concentration of 100nM significantly increased PRL mRNA synthesis in dispersed pituitary cells. The above observations are to a certain extent consistent with the results obtained by Bhandari et al (2003), who showed that sGnRH analogue stimulated the PRL mRNA synthesis in masu salmon (Oncorhynchus masou). Also Onuma et al (2005) observed the stimulatory action of sGnRH on PRL mRNA synthesis in primary pituitary cells of masu salmon.…”

Section: Discussionsupporting

confidence: 92%

The influence of sGnRH-A and antidopaminergic drug - pimozide - on prolactin mRNA synthesis in female Prussian carp (Carassius gibelio Bloch) in vivo

Chyb¹,

Socha²,

Szczerbik³

et al. 2013

CZECH J ANIM SCI

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Effects of salmon gonadotropin releasing hormone analogue (sGnRH-A) and antidopaminergic drug, pimozide, on the synthesis of prolactin mRNA in vivo in female Prussian carp (Carassius gibelio Bloch) during two different stages of the reproductive cycle were evaluated. The results showed that the lowest dose of sGnRH-A (5 μg/kg body weight) significantly stimulated the mRNA synthesis in fish during the recrudescence as well as during the preovulatory period, higher doses of this compound having no significant effect on prolactin mRNA synthesis. The blocker of dopamine receptors, pimozide, also potentiated prolactin mRNA synthesis -in recrudescent females it increased mRNA levels at the dose of 1 mg/kg, while in the preovulatory period all of the used pimozide doses (1, 5, and 10 mg/kg) were responsible for the increase of prolactin mRNA levels. Taken together, the above results suggest that gonadotropin releasing hormone (GnRH) is the factor responsible for the stimulation of prolactin synthesis, while dopamine has an inhibitory influence on the prolactin production.

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Section: Discussionsupporting

confidence: 92%

The influence of sGnRH-A and antidopaminergic drug - pimozide - on prolactin mRNA synthesis in female Prussian carp (Carassius gibelio Bloch) in vivo

Chyb¹,

Socha²,

Szczerbik³

et al. 2013

CZECH J ANIM SCI

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“…We recently demonstrated that sGnRH directly elevated neural activities of VT neurons in the PM of pre-spawning chum salmon in the Ishikari Bay (Abe and Urano, 2005). In masu salmon, administration of GnRH analogue 9 elevated the amounts of PRL mRNA in spring, when wild fish migrate from ocean through the natal river (Bhandari et al, 2003). These results support the notion that sGnRH neurons coordinately facilitate gene expression for osmoregulatory hormones, and in turn facilitate migratory behavior from SW through FW environment.…”

Section: -5 Concordant Regulation Of Osmoregulatory Hormone Genes Ansupporting

confidence: 66%

Expression of hormone genes and osmoregulation in homing chum salmon: A minireview

Makino

Onuma

Kitahashi

et al. 2007

General and Comparative Endocrinology

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Pacific salmon migrate from ocean through the natal river for spawning. Information on expression of genes encoding osmoregulatory hormones and migratory behavior is important for understanding of molecular events that underlie osmoregulation of homing salmon. In the present article, regulation of gene expression for osmoregulatory hormones in pre-spawning salmon was briefly reviewed with special reference to neurohypophysial hormone, vasotocin (VT), and pituitary hormones, growth hormone (GH) and prolactin (PRL).Thereafter, we introduced recent data on migratory behavior from SW to FW environment.In pre-spawning chum salmon, the hypothalamic VT mRNA levels increased in the males, while decreased in the females with loss of salinity tolerance when they were kept in SW.The amounts of GH mRNA in the pituitary decreased during ocean migration prior to entrance into FW. Hypo-osmotic stimulation by SW-to-FW transfer did not significantly affect the amount of PRL mRNA, but it was elevated in both SW and FW environments along with progress in final maturation. Behaviorally, homing chum salmon continued vertical movement between SW and FW layers in the mouth of the natal river for about 12 hours prior to upstream migration. Pre-spawning chum salmon in an aquarium, which allowed fish free access to SW and FW, showed that individuals with the lower plasma testosterone (T) and higher estradiol-17β (E2) levels spent longer time in FW when compared with the SW fish.Taken together, neuroendocrine mechanisms that underlie salt and water homeostasis and migratory behavior from SW to FW may be under the control of the hypothalamus-pituitary -gonadal axis in pre-spawning salmon.

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“…The presence of seasonal reproductive differences in the gh mRNA responses to GnRH is unlikely to be unique to goldfish. Seasonal differences in the effects of a GnRH analog on pituitary gh gene expression have also been reported for masu salmon (Bhandari et al 2003).…”

Section: Influences Of Gonadal Recrudescence Stagesmentioning

confidence: 81%

Seasonal effects of GnIH on basal and GnRH-induced goldfish somatotrope functions

Moussavi¹,

Wlasichuk²,

Chang³

et al. 2014

Journal of Endocrinology

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To understand how gonadotropin-inhibitory hormone (GnIH) regulates goldfish GH cell functions, we monitored GH release and expression during early, mid-, and/or late gonadal recrudescence. In vivo and in vitro responses to goldfish (g) GnIH were different, indicating direct action at the level of pituitary, as well as interactions with other neuroendocrine factors involved in GH regulation. Injection of gGnIH consistently reduced basal serum GH levels but elevated pituitary gh mRNA levels, indicating potential dissociation of GH release and synthesis. Goldfish GnRH (sGnRH and cGnRHII) injection differentially stimulated serum GH and pituitary gh mRNA levels with some seasonal differences; these responses were reduced by gGnIH. In contrast, in vitro application of gGnIH during 24-h static incubation of goldfish pituitary cells generally elevated basal GH release and attenuated sGnRH-induced changes in gh mRNA, while suppressing basal gh mRNA levels at mid-and late recrudescence but elevating them at early recrudescence. gGnIH attenuated the GH release responses to sGnRH during static incubation at early, but not at mid-and late recrudescence. In cell column perifusion experiments examining short-term GH release, gGnIH reduced the cGnRHII-and sGnRH-stimulated secretion at late recrudescence but inhibited tha action of cGnRHII only during mid-recrudescence. Interestingly, a reduction of basal GH release upon perifusion with gGnIH during late recrudescence was followed by a rebound increase in GH release upon gGnIH removal. These results indicate that gGnIH exerts complex effects on basal and GnRH-stimulated goldfish GH cell functions and can differentially affect GH release and mRNA expression in a seasonal reproductive manner.

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Seasonal changes of responses to gonadotropin-releasing hormone analog in expression of growth hormone/prolactin/somatolactin genes in the pituitary of masu salmon

Cited by 63 publications

References 33 publications

The influence of sGnRH-A and antidopaminergic drug - pimozide - on prolactin mRNA synthesis in female Prussian carp (Carassius gibelio Bloch) in vivo

The influence of sGnRH-A and antidopaminergic drug - pimozide - on prolactin mRNA synthesis in female Prussian carp (Carassius gibelio Bloch) in vivo

Expression of hormone genes and osmoregulation in homing chum salmon: A minireview

Seasonal effects of GnIH on basal and GnRH-induced goldfish somatotrope functions

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