ABSTRACT
OBJECTIVE: To investigate the influence of substance P on gonadotropin release from the pituitary as evaluated according to the final effect, i.e. the ovulation. METHODS: Stainless steel tube was implanted into the 3rd cerebral ventricle and substance P (SP), C-terminal hexapeptide of Substance P (SP6-11), Gn-RH and adrenaline were infused on the 3rd day of the cycle (proestrus). The oviducts were then isolated on the day of estrus and the ova were counted. RESULTS: SP or SP6-11 inhibited the ovulation which was not prevented by intracerebroventricular (i.c.v.) capsaicin pretreatment. The i.c. v. administration of noradrenaline on the 7-8th day of pseudopregnancy induced the ovulation which was prevented by the injection of SP immediately before noradrenaline. CONCLUSIONS: It is suggested that noradrenergic neuros which control the ovulation by influencing the release of Gn-RH into pituitary portal vessels are affected by SP-ergic neurons.
Subject(s)
Homeostasis , Ovulation/physiology , Substance P/physiology , Animals , Capsaicin/pharmacology , Cerebral Ventricles/drug effects , Enkephalin, Methionine/pharmacology , Epinephrine/administration & dosage , Epinephrine/pharmacology , Female , Gonadotropin-Releasing Hormone/administration & dosage , Gonadotropin-Releasing Hormone/pharmacology , Ovulation/drug effects , Peptide Fragments/administration & dosage , Peptide Fragments/pharmacology , Pseudopregnancy , Pyrrolidonecarboxylic Acid/analogs & derivatives , Rats , Rats, Inbred BUF , Rats, Wistar , Substance P/administration & dosage , Substance P/pharmacologyABSTRACT
We have shown that the complexation of luteinizing hormone releasing hormone, luliberin (LHRH), a hypothalamic neurohormone, by Cu(II), Ni(II), and Zn(II) may affect its basic, ovulation-inducing potency in the dose responsive manner. Some explanation of the obtained results are offered here.
