Journal article
Changes in steroid hormone profiles and ovarian histology during salmon pituitary‐induced vitellogenesis and ovulation in female New Zealand longfinned eels, Anguilla dieffenbachii gray
The Journal of experimental zoology, Vol.289(2), pp.119-129
02/01/2001
Handle:
https://hdl.handle.net/2376/110974
PMID: 11169499
Abstract
To assess whether induced vitellogenesis in longfinned eels mimics that in naturally maturing conspecifics, female eels were artificially matured and steroid hormone status and oocyte cytology during oogenesis were evaluated. Successful induction of vitellogenesis was evident from the presence of yolk granules in the ooplasm of salmon pituitary homogenate (SPH)‐injected, but not saline‐, 17‐hydroxyprogesterone‐, and/or gonadotropin‐releasing hormone‐treated fish. In SPH‐treated females, the migratory nucleus stage was reached after 33–53 days, followed by ovulation around 30 hours after induction of final maturation and ovulation. Only a portion of the germ cells matured, although resumption of vitellogenesis was seen in the majority of oocytes. In contrast, in ovaries of saline‐injected controls, the most advanced oocytes were early vitellogenic. Atretic follicles were observed in ovaries of all eels, but abundance was greater in controls than in SPH‐treated fish. SPH injections elevated plasma levels of estradiol‐17β and androgens, but not pregnenes, from within three days of treatment. Our results indicate that sex steroid levels in midvitellogenic hormone‐treated females are similar to those in wild midvitellogenic females. In contrast, differences in yolk morphology of midvitellogenic follicles were seen between SPH‐treated and wild females, especially in the second crop of midvitellogenic‐sized oocytes measuring 300–400 μm in diameter. We discuss whether the observed differences affect egg quality, and perhaps explain the short life span of captive‐bred eel larvae. J. Exp. Zool. 289:119–129, 2001. © 2001 Wiley‐Liss, Inc.
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Details
- Title
- Changes in steroid hormone profiles and ovarian histology during salmon pituitary‐induced vitellogenesis and ovulation in female New Zealand longfinned eels, Anguilla dieffenbachii gray
- Creators
- P. Mark LokmanRobert T WassHayley C SuterStephen G ScottKaren F JudgeGraham Young
- Publication Details
- The Journal of experimental zoology, Vol.289(2), pp.119-129
- Academic Unit
- UNKNOWN
- Publisher
- John Wiley & Sons, Inc; New York
- Number of pages
- 11
- Grant note
- University of Otago Research Committee The Lottery Grants Board
- Identifiers
- 99900547492001842
- Language
- English
- Resource Type
- Journal article