Areas of the Brain Stimulatory to LH and FSH Secretion

Abstract

Plasma levels of LH and FSH were determined by radioimmunoassay following electrochemical stimulation of various brain areas. Stimulation of many sites in an area of the brain beginning in the medial septum and extending through the preoptic area (POA) and anterior hypothalamic area (AHA) and terminating in the median eminence arcuate complex (MEAC) resulted in highly significant increases in plasma LH levels. Approximately 80 % of the sites in-the POA, AHA and MEAC which were found to be stimulatory to LH were also stimulatory to FSH secretion. Plasma LH levels were highest 0.5 hr after stimulation of the POA, AHA and MEAC, while FSH levels did not increase until 3.0 hr after stimulation. The significant difference in latency for onset of hormone secretion suggests that LH and FSH may be controlled by 2 separate neuronal networks which could not be resolved by the stimulus employed in this study. It was also noted that medial septal stimulation caused a much more prolonged increment in LH secretion than that observed from stimulation of other brain areas. Stimulation of the olfactory tubercle, dorsal hippocampus, lateral amygdala or corpus callosum had no effect on LH and FSH secretion under the conditions of this study. (Endocrinology88: 180, 1971)