The distribution and secretion of kallikrein in some exocrine organs of the rat.

Extractable kallikrein was quantitated in the submandibular, sublingual, and parotid glands and in the pancreas. No kallikrein was detected in the exorbital lacrimal glands and tears. The highest kallikrein concentrations (EU/ml) were in all major salivary gland secretions seen after alpha-adrenergic stimulation, less after beta-adrenergic and least after parasympathetic stimulation. When taking into account the large variations in salivary flow rate, alpha-adrenergic stimulation was in the parotid and particularly in the submandibular gland found to result in the highest kallikrein secretory activity measured by the kallikrein secretory rate(EU/min). This shows that the kallikrein-rich granular tubular cells are selectively activated through alpha-adrenergic sympathetic receptors. The differences observed in the parotid saliva were small and not always statistically significant. However, when cervical nerve stimulation was superimposed upon parasympathetic stimulation, kallikrein secretory rate as well as kallikrein concentration increased. The large individual variations in salivary gland kallikrein content and secretion and the rather small differences observed in kallikrein secretory rate after nervous stimulation of the parotid and sublingual glands, may indicate that the kallikrein-containing striated ducts are also influenced by factors other than the secretory nerves. The kallikrein concentration and secretory rate in urine was studied. A strong positive correlation between kallikrein secretory rate and fluid volume was found in urine but not in saliva.