Harvey S, Hayer S, Sloley B D
Department of Physiology, University of Alberta, Edmonton, Canada.
Regul Pept. 1993 Jan 22;43(1-2):49-56. doi: 10.1016/0167-0115(93)90406-x.
Parathyroid hormone (PTH) modulates dopamine (DA) metabolism in the rat medial basal hypothalamus (MBH) in vivo. Direct effects of PTH on MBH DA metabolism were therefore investigated in vitro. Incubation of rat MBHs for 60 min with 10(-7)-10(-5) M human PTH1-34 consistently reduced the tissue DA content and increased the DOPAC (dihydroxyphenylacetic acid) to DA ratio. This ratio was further increased in tissues incubated in 10(-5) M PTH1-34, as a result of an increase in DOPAC content. The tissue content of DOPAC and DA was unaffected by 10(-9) M PTH. The serotonin (5HT) content of the MBH was reduced by 10(-5) M PTH1-34, but concentrations of 5HT, 5-hydroxyindolacetic acid, and norepinephrine were otherwise unaffected by 10(-9)-10(-5) M PTH1-34. Concentrations of DA in the incubation media were reduced after exposure to 10(-6) or 10(-5) M PTH1-34. The uptake of 3H-labelled DA by incubated tissues was also reduced by 10(-6) M PTH1-34, as was the metabolism of 3H-labelled DA into tissue and media DOPAC. Monoamine oxidase (MAO) activities A and B were significantly increased after the incubation of the MBH with 10(-6) or 10(-5) M PTH1-34. These results further demonstrate neuromodulatory actions of PTH on dopaminergic neurons within the rat MBH in vitro, and suggest neural and/or neuroendocrine roles of PTH of central or peripheral origin.
甲状旁腺激素（PTH）可在体内调节大鼠内侧基底下丘脑（MBH）中的多巴胺（DA）代谢。因此，我们在体外研究了PTH对MBH中DA代谢的直接作用。用10⁻⁷ - 10⁻⁵ M的人PTH1 - 34孵育大鼠MBH 60分钟，持续降低组织DA含量，并增加二羟基苯乙酸（DOPAC）与DA的比率。由于DOPAC含量增加，在10⁻⁵ M PTH1 - 34中孵育的组织中该比率进一步升高。10⁻⁹ M PTH对DOPAC和DA的组织含量没有影响。10⁻⁵ M PTH1 - 34降低了MBH中的血清素（5HT）含量，但10⁻⁹ - 10⁻⁵ M PTH1 - 34对5HT、5 - 羟基吲哚乙酸和去甲肾上腺素的浓度没有其他影响。暴露于10⁻⁶或10⁻⁵ M PTH1 - 34后，孵育培养基中的DA浓度降低。10⁻⁶ M PTH1 - 34也降低了孵育组织对³H标记DA的摄取，以及³H标记DA代谢为组织和培养基中DOPAC的过程。用10⁻⁶或10⁻⁵ M PTH1 - 34孵育MBH后，单胺氧化酶（MAO）A和B的活性显著增加。这些结果进一步证明了PTH在体外对大鼠MBH内多巴胺能神经元的神经调节作用，并提示了中枢或外周来源的PTH的神经和/或神经内分泌作用。
