Date of Award:

5-1-1977

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Biology

Department name when degree awarded

Life Sciences:Biology

Committee Chair(s)

LeGrande C. Ellis

Committee

LeGrande C. Ellis

Committee

Thomas L. Bahler

Committee

Warren C. Foote

Abstract

The purpose of the research was to ascertain the effect of guanosine 3' ,5'-cyclic monophosphate on hydroxyindole-0-methyl transferase activity in laboratory female rats, a free-living population of male and female house sparrows, and bovine pineal glands obtained from the abbatoir, in vitro. The data showed that guanosine 3' ,5'-cyclic monophosphate significantly inhibited hydroxyindole-0-methyl transferase activity in all three species, but the bovine pineal preparation was the least sensitive. From these data, it appears that guanosine 3' ,5'-cyclic monophosphate acts as a second messenger to the neurotransmitter norepinephrine for the control of hydroxyindole-0-methyl transferase activity as follows: Darkness effects the release of norepinephrine at the neural synapse with the pineal parenchymal cells. Norepinephrine stimulates adenyl cyclase to form adenosine 3' ,5'-cyclic monophosphate that in turn increases N-acetyltransferase activity. Similarly, norepinephrine inhibits guanyl cyclase thereby reducing guanosine 3' ,5'-cyclic monophosphate that in turn activates hydroxyindole-0-methyl transferase thereby increasing melatonin synthesis.

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