Serum concentrations of reproductively-related circulating steroid hormones in the free-ranging lemon shark, Negaprion brevirostris
- 1) Department of Chemistry & Biological Sciences, Oregon Graduate Institute, 97006, Beaverton, OR, U.S.A.
- 2) Bimini Biological Field Station, Division of Marine Biology & Fisheries, Rosenstiel School of Marine & Atmospheric Science, University of Miami, 33149-1098, Miami, FL, U.S.A.
Synopsis: We have examined the concentrations of reproductively-related steroid hormones in 5 species of carcharhinid sharks, marine fishes possessing the unique attribute of placental viviparity. Measurements of serum estradiol, testosterone, progesterone, dihydrotestosterone, and corticosterone have provided baseline data for these hormones in both immature and adult male and female placental sharks. Our studies include: (1) changes in hormonal levels during maturation, (2) concentrations of circulating steroid hormones during peak breeding season, and (3) hormonal levels during gestation, including the collection of serial samples through and beyond birth from free-ranging lemon sharks. Our data suggest that steroids, important in regulating reproduction in higher mammals, are also essential in these cartilaginous fishes.
- 1 - sciences appliquees, technologies et medecines
- 2 - sciences biologiques et medicales
- 3 - sciences biologiques fondamentales et appliquees. psychologie
- 4 - vertebres: anatomie et physiologie, organisme dans son ensemble ou etude de plusieurs organes ou systemes
- 1 - Life Sciences ; 2 - Agricultural and Biological Sciences ; 3 - Aquatic Science
- 1 - Life Sciences ; 2 - Agricultural and Biological Sciences ; 3 - Ecology, Evolution, Behavior and Systematics