Control of LH Secretion: Role of a “Short” Feedback Mechanism1

Abstract
Implants of LH (luteinizing hormone) placed into the median eminence (ME) region of normal or castrated male and castrated female rats significantly depressed pituitary LH stores; plasma LH levels also were reduced in the castrated female rats following placement of LH in the ME. These effects were not duplicated by FSH (follicle-stimulating hormone) in the ME or by LH implants placed in the cerebral cortex or the anterior pituitary. The hypothesis is put forward that a " short" feedback loop might link synthesis and release of LH to pre-existing levels of the hormone.