Regulation of seasonal changes in circulating thyroid hormones in channel catfish /

activity.

Bibliographic Details
Main Author: Loter, Thomas C., 1972-
Format: Thesis eBook
Language:English
Published: [Place of publication not identified] : [publisher not identified] ; 1998.
Subjects:
Online Access:Link to OAKTrust copy
Description
Summary:activity.
activity. Hepatic ORD Vmax and Km, were highest in
and seasonal alterations in plasma binding proteins
April, possibly a response to elevated reproductive
catfish hepatic 011.13 was chemically similar to
changes in the phase of daily rhythms in circulating
Channel catfish, Ictalurus punctatus, were sampled at hics.
Circulating T3 levels may thus be more directly
circulating thyroid hormones were due to seasonal
circulating Ts in July may inhibit ORD activity.
coincident with highest blood protein levels.
dependent on the centrally regulated provision of T4
evidence for seasonal phase shifting in diurnal
Except for plasma T3 levels in April, the pattern of
hepatic deionization and blood protein binding. Plasma
hepatic deionization, I developed an assay to measure
hepatic outer ring deiodinase (011.I)). Channel
in January, intermediate in April and highest in July.
January whereas To binding was highest in July,
Lastly, T4 binding by the plasma was highest in
levels, or to seasonal alterations in peripheral
mammalian Type 11 and fish denominates. Hepatic []
minimal and maximal food intake, respectively. The
morning, midday, and dusk in January, April, and July
not to be due to an elevation in hepatic 011.13
retained throughout all three months providing no
significantly lower thyroid hormone concentrations in
steroids or increased food consumption, whereas high
summer increase in circulating Ta therefore appears
than on peripheral regulation of hepatic deiodinase
the morning which peaked later in the photophase was
thyroid hormone cycles. To examine seasonal changes in
thyroxine (T4) and triiodothyronine (T3) were lowest
to determine if apparent seasonal differences in
were identical in January and July, at times of
Item Description:"Major subject: Zoology".
Vita.
Physical Description:viii, 63 leaves : illustrations ; 28 cm.
Also available online.
Bibliography:Includes bibliographical references (leaves 56-62).