Cefalu W T, Pardridge W M, Chaudhuri G, Judd H L
J Clin Endocrinol Metab. 1986 Jul;63(1):20-8. doi: 10.1210/jcem-63-1-20.
The concentration of testosterone in saliva is probably in equilibrium with the concentration of cellular exchangeable testosterone in salivary gland, and these pools are a function of hormone transplant from the plasma compartment, and hormone metabolism in salivary gland cells. Both of these processes were examined in the present study using the carotid injection technique in normal and pilocarpine-stimulated ketamine-anesthetized rats. Both testosterone and estradiol were rapidly transported across salivary gland capillaries in vivo from the circulating albumin-bound pool. Estradiol, but not testosterone, was also rapidly transported into salivary gland from the circulating human sex hormone-binding globulin-bound pool. Hormone transport was several-fold greater than the capillary transport of [3H]bovine albumin, indicating that bound hormone was available for transport across salivary gland capillaries via an enhanced dissociation mechanism, with the plasma protein primarily residing in the plasma compartment. This result was confirmed by thaw-mount autoradiography, which showed diffuse distribution of [3H]testosterone in salivary gland, but vascular retention of [3H]bovine albumin. The concentration of exchangeable cellular testosterone in rat saliva was less than 4% of the total or plasma exchangeable testosterone in the rat. This marked discrepancy between the concentration of plasma and cellular exchangeable hormone suggested that there was rapid metabolism of androgen by salivary gland in vivo. This was confirmed by chromatographic separation of [3H] testosterone and labeled metabolites in homogenates of salivary gland. By 60 sec after injection, approximately 30% of the radioactivity in the salivary gland was in the form of androgen metabolites, which primarily comigrated with an androstenedione standard. The data indicate that albumin-bound testosterone, albumin-bound estradiol, and sex hormone-binding globulin-bound estradiol are all exchangeable in salivary gland capillaries. The low concentration of cellular exchangeable testosterone in salivary gland appears to be due to rapid tissue metabolism of this hormone. Thus, changes in androgen metabolism may alter salivary gland hormone concentrations independent of any change in the concentration of biologically active hormone in plasma.
唾液中睾酮的浓度可能与唾液腺中细胞可交换睾酮的浓度处于平衡状态，并且这些库是血浆隔室中激素转运以及唾液腺细胞中激素代谢的函数。在本研究中，使用颈动脉注射技术在正常和毛果芸香碱刺激的氯胺酮麻醉大鼠中检查了这两个过程。睾酮和雌二醇在体内均从循环中的白蛋白结合库快速转运穿过唾液腺毛细血管。雌二醇（而非睾酮）也从循环中的人性激素结合球蛋白结合库快速转运至唾液腺。激素转运比[3H]牛白蛋白的毛细血管转运大几倍，表明结合激素可通过增强的解离机制转运穿过唾液腺毛细血管，血浆蛋白主要存在于血浆隔室中。解冻装片放射自显影证实了这一结果，其显示[3H]睾酮在唾液腺中呈弥漫分布，但[3H]牛白蛋白则保留在血管中。大鼠唾液中可交换细胞睾酮的浓度低于大鼠总可交换睾酮或血浆可交换睾酮的4%。血浆和细胞可交换激素浓度之间的这种显著差异表明，唾液腺在体内对雄激素有快速代谢。唾液腺匀浆中[3H]睾酮和标记代谢物的色谱分离证实了这一点。注射后60秒，唾液腺中约30%的放射性呈雄激素代谢物形式，其主要与雄烯二酮标准品共迁移。数据表明，白蛋白结合的睾酮、白蛋白结合的雌二醇和性激素结合球蛋白结合的雌二醇在唾液腺毛细血管中均可交换。唾液腺中细胞可交换睾酮浓度低似乎是由于该激素的快速组织代谢。因此，雄激素代谢的变化可能会改变唾液腺激素浓度，而与血浆中生物活性激素浓度的任何变化无关。
