Annual changes in some blood constituents of female brackish waterZoarces viviparus (L.),Teleostei, with special reference to the reproductive cycle and the embryotrophe

1974 ◽  
Vol 8 (1-2) ◽  
pp. 117-123 ◽  
Author(s):  
Rolf Kristoffersson ◽  
Saara Broberg ◽  
Aimo Oikari
Keyword(s):  
Special Reference ◽  
Reproductive Cycle ◽  
Blood Constituents ◽  
Annual Changes

scholarly journals Risks of hormonally active pharmaceuticals to amphibians: a growing concern regarding progestagens

2014 ◽  
Vol 369 (1656) ◽  
pp. 20130577 ◽  
Author(s):  
Moa Säfholm ◽  
Anton Ribbenstedt ◽  
Jerker Fick ◽  
Cecilia Berg
Keyword(s):  
Adverse Effects ◽  
Special Reference ◽  
Environmental Exposure ◽  
Reproductive Cycle ◽  
Sex Differentiation ◽  
Reproductive Toxicity ◽  
Test Species ◽  
Exposure Levels ◽  
Critical Phases ◽  
Water Borne

Most amphibians breed in water, including the terrestrial species, and may therefore be exposed to water-borne pharmaceuticals during critical phases of the reproductive cycle, i.e. sex differentiation and gamete maturation. The objectives of this paper were to (i) review available literature regarding adverse effects of hormonally active pharmaceuticals on amphibians, with special reference to environmentally relevant exposure levels and (ii) expand the knowledge on toxicity of progestagens in amphibians by determining effects of norethindrone (NET) and progesterone (P) exposure to 0, 1, 10 or 100 ng l −1 (nominal) on oogenesis in the test species Xenopus tropicalis . Very little information was found on toxicity of environmentally relevant concentrations of pharmaceuticals on amphibians. Research has shown that environmental concentrations (1.8 ng l −1 ) of the pharmaceutical oestrogen ethinylestradiol (EE 2 ) cause developmental reproductive toxicity involving impaired spermatogenesis in frogs. Recently, it was found that the progestagen levonorgestrel (LNG) inhibited oogenesis in frogs by interrupting the formation of vitellogenic oocytes at an environmentally relevant concentration (1.3 ng l −1 ). Results from the present study revealed that 1 ng NET l −1 and 10 ng P l −1 caused reduced proportions of vitellogenic oocytes and increased proportions of previtellogenic oocytes compared with the controls, thereby indicating inhibited vitellogenesis. Hence, the available literature shows that the oestrogen EE 2 and the progestagens LNG, NET and P impair reproductive functions in amphibians at environmentally relevant exposure concentrations. The progestagens are of particular concern given their prevalence, the range of compounds and that several of them (LNG, NET and P) share the same target (oogenesis) at environmental exposure concentrations, indicating a risk for adverse effects on fertility in exposed wild amphibians.

A Small Expose on Bovine Pheromones: with Special Reference to Modifications of the Reproductive Cycle

2016 ◽  
pp. 33-42
Author(s):  
Kristina Nordéus ◽  
Renée Båge ◽  
Hans Gustafsson ◽  
Robert Glinwood ◽  
Lennart Söderquist
Keyword(s):  
Special Reference ◽  
Reproductive Cycle
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