Zinc hyperaccumulation in squirrelfish (Holocentrus adscenscionis) and its role in embryo viability.
Female squirrelfish (Fam. Holocentridae) can accumulate and temporarily sequester copious amounts of zinc (Zn) in their livers. There, it is initially compartmentalized before a subsequent, estrogen-triggered redistribution to the ovaries. Here we show that cellular uptake of Zn is also influenced by estrogen signaling, and that estrogen increases concentrations of the plasma Zn-binding protein vitellogenin (VTG). However, estrogen-mediated increases in VTG are not sufficient to accommodate the magnitude of hepato-ovarian Zn transfer in female squirrelfish (Holocentrus adscensionis). These findings suggest that holocentrids have acquired the ability to use hormonal cues to drive hepatic uptake and storage of Zn, signal for its physiological redistribution, and influence the capacity for systemic transport of Zn beyond the mediation of increased plasma VTG concentrations. Such specific adaptations suggest an advantage for the oocyte, which is corroborated in further studies where we determined that oocyte Zn concentrations are positively correlated with egg viability in captive-spawned squirrelfish. The novel nature of these findings underlies the importance of Zn in squirrelfish reproductive biology.
Department of Biological Sciences, Northern Kentucky University, Highland Heights, Kentucky, United States of America. thompsone1@nku.edu
E David
ED
Thompson
Gregory D
GD
Mayer
Chris N
CN
Glover
Tom
T
Capo
Patrick J
PJ
Walsh
Christer
C
Hogstrand
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D015153:Blotting, Western; D002352:Carrier Proteins / Q000097:blood / Q000378:metabolism; D002470:Cell Survival; D004625:Embryo, Nonmammalian / Q000196:embryology / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D005399:Fishes / Q000097:blood / Q000196:embryology / Q000378:metabolism*; D022781:Hepatocytes / Q000166:cytology / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008297:Male; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D010053:Ovary / Q000166:cytology / Q000378:metabolism*; D010063:Ovum / Q000166:cytology / Q000378:metabolism; D014018:Tissue Distribution / Q000187:drug effects; D014819:Vitellogenins / Q000097:blood / Q000378:metabolism; D015032:Zinc / Q000097:blood / Q000378:metabolism* / Q000493:pharmacokinetics
D002352:Carrier Proteins; D004967:Estrogens; D014819:Vitellogenins; C017800:zinc-binding protein; D004958:Estradiol; D015032:Zinc