선천성 고혈압 쥐에서 시상하부 카테콜아민성 신경계에 미치는 난소 스테로이드 호르몬의 영향

Effect of Ovarian Steroid Hormones on Catecholaminergic Nervous System in the Hypothalamus of SHR

A question whether abnormal responsiveness of hypothalamic catecholaminergic nervous system to ovarian steroid hormones in spontaneously hypertensive rats (SHR) exist was investigated. Four groups of experimental animals were prepared for SHR and normotensive Wistar rats (NW) respectively: 1) intact, 2) ovariectomized (OVX+V), 3) ovariectomized and estrogen treated (OVX+E), 4) ovariectomized and estrogen plus progesterone treated (OVX+E+P) groups. Hypothalami from experimental animals were dissected out and used for determination of alpha-adrenergic receptor binding characteristics and catecholamine contents. Norepinephrine(NE) content and Bmax of alpha1-adrenergic receptors in hypothalami were greater in intact SHR than in intact NW, but dopamine(DA) content was lower in SHR than in NW. Neither contents of NE and DA nor binding characteristics of alpha1-adrenergic receptors were different in OVX+V and OVX+E group from intact group of both SHR and NW. Kd and Bmax of alpha1-adrenergic receptors in OVX+E+P was lower than that in intact SHR but not in NW. DA content was lower in OVX+E+P than in intact group of SHR and NW. The result of the present study indicates that there is an abnormal responsiveness of hypothalamic catecholaminergic nervous system to ovarian steroid hormones in SHR which may be one of genetically-determined factors probably not responsible for the development of hypertension.