Latman N S
J Exp Zool. 1980 Jun;212(3):313-22. doi: 10.1002/jez.1402120303.
A number of previous investigations have indicated that the pituitary may directly stimulate secretion of parathyroid hormone. Others have disagreed. With the recent development of an in vitro bovine parathyroid perfusion system, the direct effect of suspected secretagogues can be assessed on a dynamic, ongoing basis. A partially purified pituitary extract (preparation A) was injected into calves. The plasma calcium increased an average of 1.1 mg/100 ml plasma. No increase of immunoreactive parathyroid hormone (iPTH) was detected, however, in the peripheral plasma prior to the increase in plasma calcium concentration. Since the peripheral plasma iPTH concentration has been shown to be relatively insensitive to changes in the secretion rate, the inability to detect a change in the iPTH concentration does not preclude a direct stimulating effect of the pituitary on the parathyroid. When preparation A was tested on in vitro perfused bovine parathyroid glands, a 30% average increase in secretion of c-iPTH (carboxy terminus) and a 56% average increase in secretion of n-iPTH (amino terminus) was observed under normocalcemic conditions. Under conditions of hypercalcemia, there was an average increase in the c-iPTH secretion rate of 60% and an average n-iPTH secretion rate increase of 88%. A failure of TSH, LH, GH, ADH, oxytocin, and prolactin to stimulate iPTH was observed. Previous reports have eliminated ACTH, MSH, and lipotropin as possible parathyroid secretagogues. The concept of a parathyroid stimulating hormone (PTSH) located in the pituitary that can directly stimulate the parathyroid gland to secrete parathyroid hormone is consistent with the results of this investigation.
此前的多项研究表明，垂体可能直接刺激甲状旁腺激素的分泌。其他研究则持有不同观点。随着体外牛甲状旁腺灌注系统的最新发展，可以在动态、持续的基础上评估可疑促分泌素的直接作用。将部分纯化的垂体提取物（制剂A）注射到小牛体内。血浆钙平均升高了1.1mg/100ml血浆。然而，在血浆钙浓度升高之前，外周血浆中未检测到免疫反应性甲状旁腺激素（iPTH）的增加。由于外周血浆iPTH浓度已被证明对分泌率的变化相对不敏感，因此无法检测到iPTH浓度的变化并不排除垂体对甲状旁腺有直接刺激作用。当在体外灌注的牛甲状旁腺上测试制剂A时，在正常血钙条件下，观察到c-iPTH（羧基末端）分泌平均增加30%，n-iPTH（氨基末端）分泌平均增加56%。在高钙血症条件下，c-iPTH分泌率平均增加60%，n-iPTH分泌率平均增加88%。观察到促甲状腺激素、促黄体生成素、生长激素、抗利尿激素、催产素和催乳素不能刺激iPTH分泌。先前的报告已排除促肾上腺皮质激素、促黑素细胞激素和促脂素作为可能的甲状旁腺促分泌素。位于垂体中的甲状旁腺刺激激素（PTSH）可直接刺激甲状旁腺分泌甲状旁腺激素这一概念与本研究结果一致。
