Distribution and disappearance of radioimmunoassayable circulating luteinizing hormone in the rat: an apparent difference between stored and released forms of the hormone

Classical conditioning: induction of luteinizing hormone and testosterone secretion in anticipation of sexual activity

A classical conditioning paradigm was used to demonstrate that male rats can learn to secrete luteinizing hormone and testosterone in anticipation of sexual activity. Sexually naïve males were exposed to a neutral stimulus and then to a sexually receptive female once daily. After exposure to the paired stimuli for 14 trials, the neutral stimulus was as effective as the female in triggering luteinizing hormone and testosterone secretion. These findings provide two novel perspectives on the control of reproductive hormone secretion in male rats: (i) environmental cues, which males learn to associate with sexual activity, induce the secretion of hormones that regulate pituitary-testis function, and (ii) classical conditioning may be used as a noninvasive method to evoke functional alterations in the secretion of luteinizing hormone and presumably the neuroendocrine pathways that mediate its release.