Changes in structure of tissues and in plasma cortisol during the spawning migration of pink salmon, <i>Oncorhynchus gorbucha</i> (Walbaum)

McBride, J. R.; Fagerlund, U. H. M.; Dye, Helen M.; Bagshaw, Joseph C.

doi:10.1111/j.1095-8649.1986.tb04934.x

Cited by 53 publications

(36 citation statements)

References 21 publications

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“…The morphological and histological data obtained during this study (McBride et al, 1986) demonstrate that both sexes of pink salmon were very close to full sexual maturity when they entered fresh water. The GSIs were already at or very near to their maximum values, and only the final stages of spermatogenesis and spermiation in males, and oocyte maturation and ovulation in females, were completed in fresh water.…”

Section: Discussionmentioning

confidence: 91%

Changes in reproductive parameters during the spawning migration of pink salmon, Oncorhynchus gorbuscha (Walbaum)

Dye¹,

Sumpter²,

Fagerlund³

et al. 1986

Journal of Fish Biology

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The hormones I78-estradio1, 17a-hydroxy-20~-dihydroprogesterone (17a,208-P), 11-ketotestosterone, testosterone, gonadotropin and also vitellogenin, were determined during the spawning migration of wild pink salmon in the Fraser and Thompson Rivers in British Columbia. This stock ofpink salmon takes approximately 2 weeks to migrate the 333 km upstream to the spawning grounds. Both sexes were at an advanced stage of sexual development when they entered fresh water. In females both the 178-estradiol and vitellogenin levels fell precipitously during the migration, to be very low at spawning, whereas the 17a,208-P level rose rapidly, to be highest at arrival on the spawning grounds. The gonadotropin level also rose rapidly during the migration, and was highest in spent fish. Testosterone was at a high level throughout, although this level decreased steadily during migration. In many respects similar endocrine changes were observed in the male. For example, in the case of androgen levels, both testosterone and 1 I-ketotestosterone fell steadily during migration but were still relatively high at spawning, whereas both gonadotropin and 17a, 208-P levels rose markedly as migration progress. However, although the qualitative changes were often similar between the sexes, the levels of 17a, 208-P, testosterone, and gonadotropin were considerably higher throughout in females than in males. It isconcluded that this stock of pink salmon is at an advanced stage of sexual development when it enters fresh water. The endocrine changes observed during this study represent those controlling the final stages of reproduction, specifically final oocyte maturation and ovulation in females, and the final stages of spermatogenesis and spermiation in males.

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Section: Discussionmentioning

confidence: 91%

Changes in reproductive parameters during the spawning migration of pink salmon, Oncorhynchus gorbuscha (Walbaum)

Dye¹,

Sumpter²,

Fagerlund³

et al. 1986

Journal of Fish Biology

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“…The interrenal tissue has been shown to be activated in maturing salmonids (Pickering and Christie 1981;McBride et al 1986) and smolts (Specker and Schreck 1982;Langhorne and Simpson 1986), suggesting a role for cortisol, a known lipolytic hormone. Growth hormone and PRL, to which SL is structurally related, have been shown to be lipolytic in juvenile salmon (Leatherland and Nuti 1981;Sheridan 1986).…”

Section: Discussionmentioning

confidence: 99%

Plasma somatolactin levels in coho salmon (Oncorhynchus kisutch) during smoltification and sexual maturation

Rand‐Weaver

Swanson

1993

Fish Physiol Biochem

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Somatolactin (SL) is a novel pituitary hormone recently characterized in several fish species. Structural analyses have shown that SL belongs to the growth hormone/prolactin family, and that it is a highly conserved protein. SL is synthesized by the periodic acid/Schiff-positive cells in the pars intermedia, but has an as yet unidentified function(s). We have recently developed a homologous radioimmunoassay for coho salmon SL and measured plasma levels of SL during two stages of the coho salmon life cycle, smoltification and sexual maturation. During smoltification, plasma levels of SL changed almost in parallel with plasma levels of thyroxine; levels increased as morphological indices of smoltification appeared and decreased as smoltification was completed. Following this period, SL levels remained low until the spring prior to spawning. In a separate study, plasma levels of SL were measured in sexually maturing coho salmon that remained in fresh water throughout their life cycle. During the year of sexual maturation, plasma levels of SL gradually increased from the spring onward, reaching peak levels at the time of spawning in November and December. These data are similar to those previously reported for sexually maturing coho salmon that were maintained in seawater prior to spawning (Rand-Weaver et al. 1992). Therefore, increases in plasma SL levels occurred in sexually maturing fish irrespective of whether they were maintained in fresh water or seawater. Peak levels at spawning were higher than those observed during smoltification. Possible roles for SL in metabolism and reproduction are discussed.

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“…However, the results from the study on pink salmon insulin and our study differ in that during the up-river migration of pink salmon there was a significant transient elevation of insulin in females, whereas we observed a significant transient elevation of insulin in males transferred to fresh water. The higher levels of insulin in the Atlantic salmon compared to the pink salmon may have been due to the fact that the Atlantics were fed throughout their captivity in net-pens whereas the pink salmon had ceased feeding during their upstream migration (McBride et al 1986). …”

Section: Discussionmentioning

confidence: 99%

“…Activation of the interrenal tissue in maturing salmonids has been clearly demonstrated (Robertson and Wexler 1959;Hane and Robertson 1959, Idler et al 1959, Phillips et al 1959Pickering and Christie 1981;McBride et al 1986). The elevated blood cortisol is undoubtedly important for mobilization of energy stores (protein catabolism, lipolysis, gluconeogenesis) during final maturation.…”

Section: Introductionmentioning

confidence: 99%

Relationship between metabolic and reproductive hormones in salmonid fish

Dickhoff

Yan

Plisetskaya

et al. 1989

Fish Physiol Biochem

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Circulating concentrations of estradiol (E2), vitellogenin (VTG), thyroxine (T4), triiodothyronine (T3) and insulin were measured in reproductively maturing four and five year-old Atlantic salmon. Blood samples were collected from the fish in seawater for one year prior to their spawning in November in fresh water. In females, E2 and VTG were low but detectable from December to July, and then increased to peak levels in September and October. Plasma levels of T4 and T3 were relatively constant in winter and spring, and decreased in July. Plasma concentration of T4 increased in November when the fish returned to fresh water. Plasma T3 levels remained low during the autumn. Both T4 and T3 levels tended to be higher in males than in females during September through November. Plasma insulin concentrations increased during the spring to peak values in May, and then decreased in June and July in fish of both sexes. There was a significant elevation of plasma insulin in males during October, and the levels in males tended to be higher than those found in females during final maturation.

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Changes in structure of tissues and in plasma cortisol during the spawning migration of pink salmon, Oncorhynchus gorbucha (Walbaum)

Cited by 53 publications

References 21 publications

Changes in reproductive parameters during the spawning migration of pink salmon, Oncorhynchus gorbuscha (Walbaum)

Changes in reproductive parameters during the spawning migration of pink salmon, Oncorhynchus gorbuscha (Walbaum)

Plasma somatolactin levels in coho salmon (Oncorhynchus kisutch) during smoltification and sexual maturation

Relationship between metabolic and reproductive hormones in salmonid fish

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