Regulation of cyclic GMP phosphodiesterase in the submandibular gland of adult rat

Cyclic GMP phosphodiesterase was investigated in the submandibular gland of the adult rat to elucidate the regulatory mechanisms of cGMP concentration in this gland. Ca2+ sensitivity was easily demonstrated as in other tissues using EGTA in the buffer for elution from DEAE-cellulose. The presence of inhibitor proteins for basal and calmodulin-activated portions of Ca2+-dependent phosphodiesterase was suggested. The inhibitor for the basal activity of Ca2+-dependent phosphodiesterase was deemed to be a heat-labile protein, which decreased Vmax, but had no effect on the Km value for cGMP. The presence of more than one kind of inhibitor for the calmodulin-activated portion of the Ca2+-dependent phosphodiesterase was also suggested. One of these, which was not absorbed on DEAE-cellulose, was a heat-labile protein which caused an increase of Km for cGMP, but no change of Vmax.

Purification of calmodulin from bovine parotid gland

Calmodulin was purified from bovine parotid gland. This calmodulin showed a single band upon sodium dodecyl sulfate polyacrylamide gel electrophoresis, and a characteristic decrease of the mobility on native gel in the presence of Ca2+. The parotid gland calmodulin activated also calmodulin-deficient cyclic nucleotide phosphodiesterase in a Ca2+-dependent fashion, and this activation was abolished by trifluoperazine, W-7 or chlorpromazine. These results may indicate clearly the existence of calmodulin in bovine parotid gland.

Distribution and regulation of mitochondrial hexokinase in rat submandibular gland

1. In rat submandibular gland, hexokinase was distributed not only in cytosol fraction but also in mitochondrial fraction. 2. Glucose-6-phosphate and ATP were most effective substances on releasing hexokinase from mitochondria. However, all the hexokinase in mitochondria could not be extracted with these substances. 3. Concentrations of glucose-6-phosphate and ATP were decreased with the administration of epinephrine in vivo. 4. Increase of the amount of mitochondria-bound hexokinase was observed for 5 min with epinephrine administration, and it returned to the control level after 10 min. 5. In rat submandibular gland, mitochondrial hexokinase may reversibly bind to and release from mitochondria as observed in brain.

Cyclic nucleotide phosphodiesterase in rat parotid gland

Cyclic nucleotide phosphodiesterase was investigated in rat parotid gland to elucidate the regulatory mechanisms for the enzyme. Cyclic nucleotide phosphodiesterase activities from DEAE-cellulose column chromatography showed two main peaks. One of them was eluted with 0.15 M KCl and was fairly specific for cGMP. This enzyme was activated by calmodulin with an increase in Vmax and with no effect on Km. The other one was eluted with 0.25 M KCl and showed a higher specificity for cAMP than for cGMP. This enzyme, however, was not activated by Ca2=nd calmodulin. The presence of calmodulin and an inhibitor substance was confirmed by DEAE-cellulose column chromatography. The inhibitor substance was protein in nature and did not inhibit cAMP phosphodiesterase. These results may indicate that cGMP in rat parotid gland, which is supposed to correlate with secretion, is regulated also by phosphodiesterase through calmodulin and an inhibitor substance.

Primary hemangiopericytoma of the heart. A case report

Hemangiopericytoma (HP) represents a rare cellular vascular tumor. The present report of primary HP of the heart in a 53-year-old Japanese male is the first of its kind. Most of the tumor masses were removed, but masses tightly adhering to both the pericardium and the epicardium were not excised because of profuse bleeding. The patient has remained free of complaints for 10 months post-operatively. Non-invasive methods including a chest X-ray, echocardiogram, and thallium-201 myocardial imaging were found to be useful adjuncts of the diagnosis of cardiac tumor.

Syntheses, analgetic activity, and physical dependence capacity of 5-phenyl-6,7-benzomorphan derivatives

The synthesis, analgetic activity, and physical dependence capacity of a large number of 5-phenyl-6,7-benzomorphan derivatives are described. Observations made during the Stevens' rearrangement of 1-benzyl-1-methyl-delta 3-piperidinium salt derivatives (V) under various conditions are discussed. The absolute configuration of the 9-demethyl series and the 2'-deoxy series is established by comparison of their ORD and CD spectra with those of 49, whose absolute configuration was previously established by X-ray crystallography. A convenient synthesis of 3H-labeled phenols using 3H3PO4 is described, as well as the preparation of 14C-labeled compounds by conventional methods.

Effects of acute starvation on carbohydrate metabolism in rat salivary glands

1. Effects of acute starvation on enzymes of carbohydrate metabolism were determined in rat submandibular and parotid glands. 2. Activities of glycolytic enzymes were high in submandibular gland, but those of pentose phosphate pathway and glycogen metabolism were high in parotid gland. 3. Enzyme activities were lowered by acute starvation. Refeeding the rats with solid diet restored the enzyme activities, but with liquid diet, only partial recoveries were found in submandibular gland.