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Response of scorbutic guinea pigs to ascorbic acid and adrenocorticotropic hormone (ACTH)

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Title Response of scorbutic guinea pigs to ascorbic acid and adrenocorticotropic hormone (ACTH)
Names Riker, Joseph Thaddeus III (creator)
Bogart, Ralph (advisor)
Date Issued 1964-03-27 (iso8601)
Note Graduation date: 1964
Abstract Thirty-six female guinea pigs were placed on a scorbutogenic
diet for 14 days and then divided into groups of four. Three groups
received adrenocorticotropic hormone (ACTH) with each group given
10, 20, or 40 units. Three groups each received 50 mg of ascorbic
acid and three groups received 50 mg of ascorbic acid plus ACTH at
the level of either 10, 20, or 40 units.
Blood samples were drawn from all animals by heart puncture
prior to treatment and one, two, and four hours after treatment. The
plasma from these samples was then chemically analyzed for its
a scorbic acid concentration by the 2, 4-dinitrophenylhydrazine micro-method of Lowry, Lopez, and Bessey (16).
The results of the chemical analyses showed that when ACTH
is given alone there is no difference between the time intervals, but
there is a significant difference (p < .05) between the levels given.
The ascorbic acid alone showed a significant change with time (p < .005). A rapid increase in the plasma ascorbic acid concentration
occurred at one hour, followed by a decline at two and four hours.
When ascorbic acid plus ACTH is given there is a significant difference
(p < .005) with time, in that the ascorbic acid plus ACTH showed
a more rapid decline at two and four hours than ascorbic acid alone
did. There is also a significant difference (p < .005) in the response
with the different levels of ACTH. Forty units of ACTH showed a
higher plasma ascorbic acid concentration at one hour than 20 units;
however, the 10-unit level showed the highest concentration at one
hour of all the levels tested. The 40 and 20 units appear to cause a
pharmacological dose response, while 10 units may be nearer the
physiological dose level.
These results are interpreted as being due to two possible
body responses. One is that the ACTH increases the tissue ascorbic
acid absorption. The other is that the ascorbic acid corrects the
ascorbic acid:cholesterol ratio increasing the hormone production
under the influence of ACTH, and increases the peripheral metabolism
of these hormones.
It is felt that further work on the effects of ACTH on ascorbic
acid should include studies on the urinary excretion values, tissue
reabsorption times, and should also include the use of radioactive
tracers.
Genre Thesis/Dissertation
Topic Vitamin C
Identifier http://hdl.handle.net/1957/48804

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