Modulation of the noradrenergic activity index by neural stimulus, and its participation in ovarian androstenedione release during the luteal phase

Abstract

Objective: To investigate the participation of catecholamines in the association between peripheral innervation and luteal steroidogenesis. Design: Animal study. Setting: University animal laboratory. Animal(s): Six to eight virgin adult Holtzman-strain female rats in control and experimental groups on diestrus days 1 and 2. Intervention(s): Removal of the coeliac ganglion-superior ovarian nerve-ovary system, with catecholaminergic agonist or antagonist added in the ganglion compartment (experimental group only). The control group received no treatment. Main Outcome Measure(s): Ovarian neurotransmitters and their catabolites measured by reverse-phase highpressure liquid chromatography, and A2 measured by radioimmunoassay. Result(s): On day 1, dopamine and catabolite increased whereas norepinephrine decreased, and the noradrenergic neuronal activity index was higher. On day 2, dopamine levels decreased, norepinephrine increased, and dopaminergic neuronal activity was higher. The release of A2 was decreased by addition of norepinephrine to the ganglions on day 1, but was increased by the norepinephrine antagonist on day 2. Hence, norepinephrine increased A2 release, and propranolol diminished it. Conclusion(s): Ganglionic activity is modified by noradrenergic stimulus, leading to different ovarian A2 release profiles. The peripheral nervous system is a modulator in these homeostatic mechanisms.