Evaluation of Diel Variation in Androgen Levels of Rainbow Trout, Salmo gairdneri

Schreck, Carl B.; Lackey, Robert T.; Hopwood, M. L.

doi:10.2307/1442748

Cited by 22 publications

(14 citation statements)

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“…Later, between weeks 6 and 12, sperm production was more closely correlated with the plasma GTH level. This agrees with data in the literature stating that gonadotropin is involved in sperm release (Clemens and Grant, 1965 ;Yamazaki and Donaldson, 1968 (Schreck, Lackey and Hopwood, 1972 ;Idler, Horne and Sangalang, 1971). Androgens could also be involved in spermiation, and high levels may be required to stimulate sperm release ( fig.…”

Section: Discussionsupporting

confidence: 92%

The spermiation period in the rainbow trout (Salmo gairdneri). Plasma gonadotropin and androgen levels, sperm production and biochemical changes in the seminal fluid

Sánchez-Rodríguez¹,

Escaffre²,

Marlot³

et al. 1978

Ann. Biol. anim. Bioch. Biophys.

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Summary. Plasma immunoreactive t-GTH and androgens, sperm production and biochemical changes in seminal fluid were studied during the spermiation period in rainbow trout. The volume of sperm collected by hand-stripping was very low (< 0.1 ml) at the onset of spermiation, increased slowly during the next 4 weeks and sharply thereafter. Plasma t-GTH was high (6 ng/mi) at the onset and then decreased ; the sharp rise in sperm production started when circulating androgens had reached maximum values. In a second phase (b-12 weeks), the elevation in sperm production was strongly correlated wth plasma t-GTH, while plasma androgens fluctuated. Spermatocrit did not vary significantly during the period studied so that increased sperm production corresponded to an elevation in spermatozoal production. During spermiation Na + ionic concentration in the seminal fluid increased sharply and that of K + only slightly. Total protein in the seminal fluid decreased significantly after 8 weeks.Introduction.

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Section: Discussionsupporting

confidence: 92%

The spermiation period in the rainbow trout (Salmo gairdneri). Plasma gonadotropin and androgen levels, sperm production and biochemical changes in the seminal fluid

Sánchez-Rodríguez¹,

Escaffre²,

Marlot³

et al. 1978

Ann. Biol. anim. Bioch. Biophys.

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“…The first occurred between the months of August and November, and coincided with rapid increases in GSIs and population of testes with mature germ cells. A similar rise in serum T level is seen in other species at this time and is thought to regulate male germ cell differentiation (e.g., Schreck et al 1972;Billiard et al 1978). The second rise in T occurred just prior to the spawning season, and coincided with the rapid increase in the levels of 11-KT.…”

Section: Discussionsupporting

confidence: 54%

Endocrine and gonadal changes during the annual reproductive cycle of the freshwater teleost,Stizostedion vitreum

Malison

Procarione

Barry

et al. 1994

Fish Physiol Biochem

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The annual reproductive cycle of walleye (Stizostedion vitreum) was characterized by documenting changes in gonadal development and serum levels of estradiol-17β (E2), testosterone (T), 17α,20β-dihydroxy-4-pregnen-3-one (17,20-P), and 11-ketotestosterone (11-KT) in wild fish captured from upper midwestern lakes and rivers throughout the year. Fish from the populations used in this study spawn annually in early- to mid-April. Walleye showed group synchronous ovarian development with exogenous vitellogenesis beginning in autumn. Oocyte diameters increased rapidly from ∼ 200 μm in October to ∼ 1,000 μm in November, and reached a maximum of 1,500 μm just prior to spawning. Changes in gonadosomatic indices (GSIs) paralleled changes in oocyte diameters. Serum E2 levels in females increased rapidly from low values in October (< 0.1 ng ml(-1)) to peak levels of 3.7 ng ml(-1) in November, coinciding with the period of the most rapid ovarian growth. Subsequently, E2 levels decreased from December through spawning. Serum T levels exhibited a bimodal pattern, increasing to 1.6 ng ml(-1) in November, and peaking again at 3.3 ng ml(-1) just prior to spawning. We detected 11-KT in the serum of some females at concentrations up to 5.6 ng ml(-1), but no seasonal pattern was apparent. In this study (unlike our results in a related study) 17,20-P was not detected. In males, differentiation of spermatogonia began in late August, and by January the testes were filled (> 95% of germ cells) with spermatozoa. Mature spermatozoa could be expressed from males from January through April. GSIs ranged from 0.2% (post-spawn) to 3.2% (pre-spawn). Serum T levels rose from undetectable levels in post-spawn males to 1.6 ng ml(-1) by November, remained elevated throughout the winter, and peaked at 2.8 ng ml(-1) I prior to spawning. Levels of 11-KT in males remained low (< 10 ng ml(-1), from post-spawning through January, then increased significantly by March and peaked just prior to spawning at 39.7 ng ml(-1). Our results indicate that vitellogenesis and spermatogenesis are complete or nearly so, in walleye by early winter, and suggest that it may be possible to induce spawning in this species several months prior to the normal spawning season by subjecting fish to relatively simple environmental and hormonal treatments.

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“…In this latter study, a proposal was made that the drop might be due to a natural diurnal variation of androgen secretion. However, no diurnal pattern of either T or 11-KT release was found in the bluebanded goby (Lythrypnus dalli) (Lorenzi et al, 2008) and, in the two studies in which both possibilities were specifically tested (i.e., handling v. diurnal changes), it was only the repeatedly handled fish that showed a significant drop in plasma androgen concentrations (Schreck, 1972;Pickering et al, 1987). Another study on rainbow trout and brown trout (Salmo trutta) suggested that the drop could be mimicked by implanting cortisol (Carragher et al, 1989).…”

Section: Is It Worth Measuring Conjugated Steroids?mentioning

confidence: 99%

“…A perceived advantage of the non-invasive procedure is that a fish can be sampled both before and after a behavioural interaction and, thus, potentially act as its own control. However, it has been noted in a number of studies (Schreck, 1972;Pickering et al, 1987;Scott & Canario, 1990;Kubokawa et al, 1999;Vermeirssen et al, 2000) that fish sampling is followed within 30 to 60 min by a significant decrease in plasma androgen concentrations. A similar significant decrease was found in rate of release of 11-KT into water by male sticklebacks (Sebire et al, 2007) and in the concentration of 11-KT in the urine of male tilapia (Oliveira et al, 2005).…”

Section: Is It Worth Measuring Conjugated Steroids?mentioning

confidence: 99%

Non-invasive measurement of steroids in fish-holding water: important considerations when applying the procedure to behaviour studies

Scott¹,

Hirschenhauser²,

Bender³

et al. 2008

Behav

109

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SummaryFish behaviourists are increasingly turning to non-invasive measurement of steroid hormones in holding water, as opposed to blood plasma. When some of us met at a workshop in Faro, Portugal, in September, 2007, we realised that there were still many issues concerning the application of this procedure that needed resolution, including: Why do we measure release rates rather than just concentrations of steroids in the water? How does one interpret steroid release rates when dealing with fish of different sizes? What are the merits of measuring conjugated as well as free steroids in water? In the 'static' sampling procedure, where fish are placed in a separate container for a short period of time, does this affect steroid releaseand, if so, how can it be minimised? After exposing a fish to a behavioural stimulus, when is the optimal time to sample? What is the minimum amount of validation when applying the procedure to a new species? The purpose of this review is to attempt to answer these questions and, in doing so, to emphasize that application of the non-invasive procedure requires more planning and validation than conventional plasma sampling. However, we consider that the rewards justify the extra effort.

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Evaluation of Diel Variation in Androgen Levels of Rainbow Trout, Salmo gairdneri

Cited by 22 publications

References 0 publications

The spermiation period in the rainbow trout (Salmo gairdneri). Plasma gonadotropin and androgen levels, sperm production and biochemical changes in the seminal fluid

The spermiation period in the rainbow trout (Salmo gairdneri). Plasma gonadotropin and androgen levels, sperm production and biochemical changes in the seminal fluid

Endocrine and gonadal changes during the annual reproductive cycle of the freshwater teleost,Stizostedion vitreum

Non-invasive measurement of steroids in fish-holding water: important considerations when applying the procedure to behaviour studies

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