In order to study, the central and peripheral effects of oxytocin, vasopressin and histamine on the steroid (estrogen, progesterone and cortisol) secretion, the following research program was conducted. Regarding the earlier studies reveal different and controversial results in this studies. Intracerebroventricular cannulation and peripheral injection are two main ways for importing the chemical substances in the central nevvous system. Blood brain barrier as the gate of entrance conflicts with peripheral injections. But Intracerebroventriculary cannulation by-passes this barrier. Two-stage study designed to compare the central and peripheral effects in sheep. In the fisrt stage 4 male sheep and 1 female sheep were intra-cerebroventriculary cannulated with needle 18 gauge. The cannula placed in lateral ventricle of the brain. The exact point was confirmed by the extraction of cerebro-spinal fluid from cannula and X-ray graphy. These sheep were kept individually and injected with antibiotics (pen-strep) for 5 days. Unfortunately, the circumstances were not strile enough and the infection was was main reason of 3 sheep death. In second stage 4 female sheep were intravenously (jugular vein) injected by 0, 125, 250 and 500 nano mol of the vasopressin, oxytocin and histamine. Each sheep was individually injected for 4 days and the blood samples were collected via jugular vein 3 hours later. Blood serum were analyzed by CLIA and ELFA methods as the accurate way of evaluation. The lab test measured estrogen, progesterone and cortisol. The data were analyzed by GLM procedure of SAS statistical software analysis and the averages were compared by Duncan’s method. Results showed that vasopressin increased cortisol level at 125 nM significantly (p ) and interestingly reduced this steroid at 250 and 500 nM (p ) without any effect on amount of estrogene and progesterone in any dosages. In spite of the similarity of molecules oxytocin did not affect the cortisol secretion except at 250 nM (p ). It also increased estrogene secretion at 125 nM (p ) and decrease the same steroid at 500 nM (p ) without ant effect on progestrone secretion in any dosages. Finally, injection of histamine did not change any steroid level (estrogen, progestone and cortisol) at any dosages. It might be concluded which posterior pituitary hormones may act peripherally on different steroid secretio including estrogen and cortisol. In addition this effects on the stroid secretion might consecutive of their short half-life and absence of oragn receptors peripherally. Keywords : Vasopressin, Oxytocin, Histamine, Streoids