Reproductive biology and endocrinology of greenback flounder Rhombosolea tapirina (GÜnther 1862)

1999 ◽  
Vol 50 (1) ◽  
pp. 35 ◽  
Author(s):  
C. W. Barnett ◽  
N. W. Pankhurst
Keyword(s):  
Reproductive Biology ◽  
Oocyte Maturation ◽  
Plasma Concentrations ◽  
Reproductive Development ◽  
Gonadal Development ◽  
Oocyte Development ◽  
Oocyte Size ◽  
Frequency Distributions ◽  
Final Oocyte Maturation ◽  
The Relationship

The relationship between patterns of gonadal development and endocrine changes during reproductive development was examined in the greenback flounder (Rhombosolea tapirina). Oocyte size–frequency distributions showed that female greenback flounder have group synchronous oocyte development, and that there are multiple ovulations. Plasma and ovarian concentrations of testosterone (T) and 17β-oestradiol (E2) were elevated in association with vitellogenesis. Plasma concentrations of 17,20β-dihydroxy-4-pregnen-3-one (17,20βP) were significantly elevated in ovulated females, whereas ovarian concentrations of 17,20βP were elevated in association with final oocyte maturation (FOM) and ovulation. Plasma concentrations of 17,20βP-sulfate but not 17,20βP-glucuronide were elevated in association with FOM and ovulation. Changes in macroscopic testis stage were not accompanied by significant changes in proportions of gamete types in the testis. Plasma concentrations of T were elevated in spermatogenic and partially spermiated males. No significant changes in plasma 11-ketotestosterone (11KT), 17,20βP, 17,20βP-sulfate and 17,20βP-glucuronide were detected with change in testis stage.

Reproductive biology of the freshwater catfish, Tandanus tandanus Mitchell, in the Gwydir River, Australia. I. Structure of the gonads

1977 ◽  
Vol 28 (2) ◽  
pp. 139 ◽  
Author(s):  
TLO Davis
Keyword(s):  
Reproductive Biology ◽  
Oocyte Maturation ◽  
Reproductive Cycle ◽  
Germ Cells ◽  
Complicated Structure ◽  
Histological Changes ◽  
Macroscopic Appearance ◽  
Freshwater Catfish ◽  
Clear Cut ◽  
The Relationship

The gross morphology and histology of the gonads of T. tandanus were examined as a preliminary to describing the reproductive cycle of this species in the Gwydir River. The macroscopic appearance of the gonads at different stages of maturity is described. The complicated structure of the testes made it difficult to classify them into well-defined stages of maturity. The relationship between the stage of maturity of the ovaries and the histological changes associated with oocyte maturation was clear cut. Six spermatogenetic stages were recognized; primary germ cells, spermatogonia, primary spermatocytes, secondary spermatocytes, spermatids, and spermatozoa. The sequence of oocyte maturation was divided into nine stages; chromatin nucleolus, early perinucleolus, late perinucleolus, yolk vesicle, primary yolk, secondary yolk, tertiary yolk, and ripe egg stage. Atresia was observed in some oocytes from the primary yolk stage onwards. The sequence of yolk resorption in atretic oocytes is described.

Reproductive biology and endocrine regulation of final oocyte maturation of captive white bass

1997 ◽  
Vol 51 (2) ◽  
pp. 234-250 ◽  
Author(s):  
C. C. Mylonas ◽  
Y. Magnus ◽  
Y. Klebanov ◽  
A. Gissis ◽  
Y. Zohar
Keyword(s):  
Reproductive Biology ◽  
Oocyte Maturation ◽  
Endocrine Regulation ◽  
White Bass ◽  
Final Oocyte Maturation

scholarly journals Delayed implantation in giant pandas: the first comprehensive empirical evidence

Reproduction ◽  
2009 ◽  
Vol 138 (6) ◽  
pp. 979-986 ◽  
Author(s):  
Hemin Zhang ◽  
Desheng Li ◽  
Chendong Wang ◽  
Vanessa Hull
Keyword(s):  
Reproductive Biology ◽  
Giant Panda ◽  
Reproductive Development ◽  
Mammary Glands ◽  
Strongly Correlated ◽  
Physiological Changes ◽  
Giant Pandas ◽  
Delayed Implantation ◽  
Infant Birth ◽  
First Time

Successful conservation of an endangered species relies on a good understanding of its reproductive biology, but there are large knowledge gaps. For example, many questions remain unanswered with regard to gestation and fetal development in the giant panda. We take advantage of a sample size that is unprecedented for this species (n=13) to explore patterns in reproductive development across individuals at the China Conservation and Research Center for the Giant Panda. We use ultrasound techniques on multiple giant pandas for the first time to empirically confirm what has long been suspected that pandas exhibit delayed implantation of the embryo. We also show that the duration of postfetal detection period is remarkably similar across individuals (16.85±1.34 days). Detection of fetus by ultrasound was strongly correlated to the peak in urinary progesterone (r=0.96, t=8.48, d.f.=8, P=0.0001) and swelling in the mammary glands (r=0.79, t=3.61, d.f.=8, P=0.007) and vulva (r=0.91, t=6.40, d.f.=8, P=0.0002) of adult females. When controlling for both the duration of the total gestation period and the postfetal detection period, infant birth weight was only significantly predicted by the latter (β=11.25, s.e.m.=4.98, t=2.26, P=0.05), suggesting that delayed implantation increases flexibility in the timing of birth but is not important in dictating infant growth. This study informs reproductive biology by exploring the little-studied phenomenon of delayed implantation in relationship to physiological changes in pregnant giant panda females.

scholarly journals Optimal dose of HCG for final oocyte maturation in IVF cycles: absence of evidence?

2009 ◽  
Vol 19 (1) ◽  
pp. 52-58 ◽  
Author(s):  
Ioanna Tsoumpou ◽  
Javaid Muglu ◽  
Tarek A Gelbaya ◽  
Luciano G Nardo
Keyword(s):  
Oocyte Maturation ◽  
Optimal Dose ◽  
Final Oocyte Maturation ◽  
Absence Of Evidence
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