Suppression of Noradrenaline-Induced Ovulation by Administration of Substance P into the Third Cerebral Ventricle in Pseudo-Pregnant Rats

High Substance P (SP) content in hypothalamus [1] and especially in its anterior part connected with hypophysiotropic area suggests the possibility of this peptide involvement in the regulation of gonadotropin release. Fluctuation of SP and LH-RH contents in the hypothalamus during the estrous cycle in the rat indicate the role of SP in the control of reproduction in female rat [2,3]. The data on the effect of SP on hypophysical endocrine function are rather contradictory. In pituitaries incubated in vitro some activity of SP was demonstrated in the release of luteinizing and folliclestimulating hormones [4]. Administration of SP into the 3rd cerebral ventricle of ovariectomized female rats elevated plasma LH levels [5].