AbstractsMedical & Health Science

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

by Joseph Thaddeus III Riker

Institution: Oregon State University
Department: Animal Science
Degree: MS
Year: 1964
Keywords: Vitamin C
Record ID: 1585279
Full text PDF: http://hdl.handle.net/1957/48804


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.