Garcia R, Kondo K, Scholkens B, Boucher R, Genest J
Can J Physiol Pharmacol. 1977 Oct;55(5):983-9. doi: 10.1139/y77-135.
Tonin (an enzyme present in rat submaxillary gland and saliva) has previously been shown to be able, unlike renin and reninlike substances, to release angiotensin II either directly by acting on an appropriate substrate or from angiotensin I. The administration of a beta-adrenergic drug, isoproterenol, produces a rise of tonin concentration in saliva without affecting its concentration in the submaxillary gland. Prior administration of a beta blocker, propranolol, partially prevents this effect. The administration of theophylline increases the tonin concentration in both saliva and the submaxillary gland, whereas dibutyryl cyclic AMP increases tonin concentration in the former. These results suggest that beta-adrenergic stimulation enhances both tonin release into the saliva and tonin synthesis in the submaxillary gland, and that these effects might be mediated by cyclic AMP. Infusion of angiotensin II blocked the stimulatory effect of isoproterenol on salivary tonin. 1Sar-8Ile-angiotensin II is both a weak antagonist of angiotensin II in this respect and a strong agonist in terms of blocking the effect of isoproterenol another role mirrored in other physiological mechanisms of derivatives of angiotensin II.
托宁（一种存在于大鼠下颌下腺和唾液中的酶）先前已被证明，与肾素和肾素样物质不同，它能够通过作用于合适的底物直接释放血管紧张素II，或者从血管紧张素I释放血管紧张素II。给予β-肾上腺素能药物异丙肾上腺素会使唾液中托宁浓度升高，而不影响其在下颌下腺中的浓度。预先给予β受体阻滞剂普萘洛尔可部分阻止这种效应。给予茶碱会增加唾液和下颌下腺中的托宁浓度，而二丁酰环磷腺苷会增加前者中的托宁浓度。这些结果表明，β-肾上腺素能刺激增强了托宁向唾液中的释放以及下颌下腺中托宁的合成，并且这些效应可能由环磷腺苷介导。输注血管紧张素II可阻断异丙肾上腺素对唾液托宁的刺激作用。1-肌氨酸-8-异亮氨酸血管紧张素II在这方面既是血管紧张素II的弱拮抗剂，又是阻断异丙肾上腺素作用的强激动剂，血管紧张素II衍生物的其他生理机制也反映了这种双重作用。
