Date of Award

Spring 1987

Project Type

Dissertation

Program or Major

Animal and Nutritional Sciences

Degree Name

Doctor of Philosophy

Abstract

To investigate the role of catecholamines and biogenic amines in the control of bovine luteal steroidogenesis, studies were conducted utilizing collagenase-dispersed luteal cells in a short-term incubation system. Studies designed to assess the role of catecholamines showed that the stimulatory response to the primary catecholamines norepinephrine and epinephrine was mediated by both $\beta\sb{1}$- and $\beta\sb{2}$- adrenergic receptors. The alternative pathway catecholamines octopamine, synephrine and deoxyepinephrine enhanced basal progesterone production, and this response was mediated by $\beta$-adrenergic receptors. Analysis of luteal tissue using high performance liquid chromatography showed nondetectable levels of norepinephrine and epinephrine. The in vivo administration of norepinephrine and epinephrine significantly stimulated luteal steroidogenesis without altering circulating levels of luteinizing hormone.

The addition of serotonin or 5-methoxytryptamine to luteal cell incubations increased the production of progesterone in a dose-dependent manner. The response to serotonin was mediated by a serotonin-1 receptor, which may not be associated with adenylate cyclase. Analysis of bovine luteal tissue using high performance liquid chromatography demonstrated the presence of serotonin, and showed that the concentration of serotonin varied with the stage of luteal development. Administration of serotonin in vivo resulted in significantly elevated levels of plasma progesterone, which were independent of changes in luteinizing hormone.

These results support the concept that a variety of biogenic amines influence bovine luteal steroidogenesis.

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