Date of Award:

5-1-1970

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Biology

Department name when degree awarded

Physiology

Committee Chair(s)

LeGrande C. Ellis

Committee

LeGrande C. Ellis

Committee

James Gessaman

Committee

T. M. Farley

Abstract

Pineal hydroxyindole-0-methyl transferase (HIOMT) activity of the House Sparrow was found to have an annual cycle. During seasons of reproductive activity, HIOMT activity was minimal in contrast to the increased HIOMT activity that occurred during the seasons of reproductive quiescence. The lag in response between increase in testes weight and change in pineal HIOMT activity and the fact that testes can increase in weight with an increase of pineal HIOMT activity suggests that the annual cycling of HIOMT activity and melatonin synthesis by the pineal gland is not responsible for the annual cycles in reproduction of the House Sparrow. However, this is consistent with the concept that the pineal gland acts as a neuroendocrine transducer mediating effects of light and dark on reproduction. When House Sparrows were subjected to continuous red light, HIOMT activity was less than was observed for birds kept in continuous darkness. White light regimes, deficient in red light increased HIOMT activity. Testosterone injection appeared to have no effect on pineal HIOMT activity.

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