Stress and adrenocorticosteroid dynamics in the goldfish, Carassius auratus

1975 ◽  
Vol 53 (8) ◽  
pp. 1012-1020 ◽  
Author(s):  
James N. Fryer

In goldfish serum, cortisol was found to constitute 77.6% of the adrenocorticosteroids measured by a competitive protein-binding radioassay. Adult goldfish maintained on a photoperiod of 14 h light: 10 h dark in November exhibited no significant variation in serum corticosteroid concentration throughout the 24-h cycle. Goldfish maintained in an 8L:16D photoperiod in June exhibited two peaks in serum adrenocorticosteroid concentration. Four hours before the onset of the light period and 4 h after the onset of the light period, serum corticosteroids were significantly higher than those observed at the midpoint of the dark period. After sham injection, swimming in shallow water, or a thermal shock, but not a handling disturbance, circulating levels of corticosteroids were significantly higher than in undisturbed fish. Betamethasone injected 24 h before a thermal stress completely blocked the stress-induced increase in serum corticosteroids observed in vehicle-injected and uninjected goldfish, demonstrating the potency of this steroid as a blocker of the pituitary–interrenal axis in this species.

1974 ◽  
Vol 31 (7) ◽  
pp. 1240-1242 ◽  
Author(s):  
Richard E. Spieler

Serum cortisol from serially sampled goldfish (Carassius auratus) did not demonstrate a stress-evoked increase (P >.05) until 10–22 min after initial capture. This response did not differ (P > 0.5) among fish sampled at the beginning, middle, and end of a 12-h light period.


1979 ◽  
Vol 57 (3) ◽  
pp. 665-669 ◽  
Author(s):  
Richard E. Spieler ◽  
Teresa A. Noeske

Goldfish maintained on a 12 h light: 12 h dark photoperiod (light onset 0800 hours) and sampled at one of six different times of day had significant differences in both serum triiodothyronine (T3) and thyroxine (T4) levels depending on the time of day of sampling. Hormone titers were determined by commercial radioimmunoassay kits. Maximum levels for T3 and T4 occurred at 1600 hours; minimum levels occurred during the 4 h preceding the onset of light (0400- and 0800-hour samples). There was no apparent effect of sampling stress (< 15 min) on titers of T3 and T4.


1977 ◽  
Vol 55 (10) ◽  
pp. 1656-1670 ◽  
Author(s):  
Greg P. Busacker ◽  
Walter Chavin

As the uptake, distribution, and turnover of epinephrine and norepinephrine are largely unknown in teleosts, the relative tissue affinities for these circulating catecholamines were evaluated in the goldfish, Carassius auratus L. Since sufficient circulating levels of catecholamines available for uptake by tissues in vivo are a transient event occurring after stress, it was decided to investigate the uptake and decline of radiolabeled catecholamines over a short period of time, noting that uptake would coincide with high endogenous levels from handling stress while decline would be unaffected by stress. Fish injected with l-[3H]norepinephrine and dl-[carbinol-14C]epinephrine were killed from 0.5 to 1024 min postinjection, and the catecholamine radiolabels determined in 19 tissues. Six different uptake and retention patterns for individual tissues were present, but all tissues examined showed preference for the norepinephrine radiolabel. Among the excretory mechanisms in the goldfish, the liver is prominent in catecholamine elimination via the bile. A blood–brain barrier appears present for epinephrine, but not for norepinephrine; epinephrine is excluded from the hypothalamus and pituitary. Further, adipose tissue takes up only norepinephrine. In some teleostean tissues, therefore, the two catecholamines are handled differently than in the comparable mammalian tissues.


Author(s):  
Waykin Nopanitaya ◽  
Joe W. Grisham ◽  
Johnny L. Carson

An interesting feature of the goldfish liver is the morphology of the hepatic plate, which is always formed by a two-cell layer of hepatocytes. Hepatic plates of the goldfish liver contain an infrequently seen second type of cell, in the centers of plates between two hepatocytes. A TEH study by Yamamoto (1) demonstrated ultrastructural differences between hepatocytes and centrally located cells in hepatic plates; the latter were classified as ductule cells of the biliary system. None of the previous studies clearly showed a three-dimensional organization of the two cell types described. In the present investigation we utilize SEM to elucidate the arrangement of hepatocytes and bile ductular cells in intralobular plates of goldfish liver.Livers from young goldfish (Carassius auratus), about 6-10 cm, fed commercial fish food were used for this study. Hepatic samples were fixed in 4% buffered paraformaldehyde, cut into pieces, fractured, osmicated, CPD, mounted Au-Pd coated, and viewed by SEM at 17-20 kV. Our observations were confined to the ultrastructure of biliary passages within intralobular plates, ductule cells, and hepatocytes.


Author(s):  
Tetsuaki Osafune ◽  
Shuji Sumida ◽  
Tomoko Ehara ◽  
Eiji Hase ◽  
Jerome A. Schiff

Changes in the morphology of pyrenoid and the distribution of RuBisCO in the chloroplast of Euglena gracilis were followed by immunoelectron microscopy during the cell cycle in a light (14 h)- dark (10 h) synchronized culture under photoautotrophic conditions. The imrnunoreactive proteins wereconcentrated in the pyrenoid, and less densely distributed in the stroma during the light period (growth phase, Fig. 1-2), but the pyrenoid disappeared during the dark period (division phase), and RuBisCO was dispersed throughout the stroma. Toward the end of the division phase, the pyrenoid began to form in the center of the stroma, and RuBisCO is again concentrated in that pyrenoid region. From a comparison of photosynthetic CO2-fixation with the total carboxylase activity of RuBisCO extracted from Euglena cells in the growth phase, it is suggested that the carboxylase in the pyrenoid functions in CO2-fixation in photosynthesis.


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