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Biomedical subjects

K D Bhoola

Publications and source records attributed to K D Bhoola.

At least 127 records · Page 7Linked to original sources
PubMed1974

Electrophoresis of isolated secretory granules from guinea-pig submaxillary gland.

1 The nature of the surface charge on secretory granules from the submaxillary gland of the guinea-pig has been studied by electrophoresis of the isolated granules. The granules suspended in buffered sucrose solutions move to the anode.2 Divalent ions reduce the anodal movements of the granules. Calcium and magnesium neutralize the net surface charge of the granules. This result supports the hypothesis that the electrostatic surface charge which can be reduced by calcium ions may be a major factor in controlling the fusion of secretory granules to the cell membrane, before release by exocytosis.3 The mechanisms which couple membrane events with enzyme or hormone release from secretory glands are considered.

Animals↗
PubMed1973

Biosynthesis of noradrenaline in organ cultured hearts.

In hearts of newborn mice, maintained in organ culture in an in vitro environment, noradrenaline levels were reduced after 24 h but subsequently recovered, reaching at three days values significantly greater than those found at birth. The increased synthesis of noradrenaline was blocked by the inhibitor of tyrosine hydroxylase, alpha-methyl tyrosine methyl ester. The site and control of noradrenaline biosynthesis in cultured newborn hearts are discussed.

Animals↗
PubMed1973

The influence of androgens on enzymes (chymotrypsin-and trypsin-like proteases, renin, kallikrein and amylase) and on cellular structure of the mouse submaxillary gland.

1. The effect of age and androgen level on enzyme activity and cellular structure has been determined in the mouse submaxillary gland.2. A new protease which resembles chymotrypsin in its substrate specificity has been characterized in the gland.3. Activity of the chymotrypsin- and trypsin-like proteases and renin increased considerably in male mice concomitantly with proliferation of granules in the secretory tubules of the gland.4. The androgen dependence of the chymotrypsin- and trypsin-like enzymes, renin and the organelles within the secretory tubules was confirmed in castrated male mice. The activity of these enzymes increased and correlated with the appearance of intracellular granules in the secretory tubules when the castrated male mice and in addition female mice were treated with testosterone preparations.5. Kallikrein, a closely related protease, and amylase increased in activity with age but showed no sex-linked differences.6. The results suggest that kallikrein is sequestered in acinar cells whereas the androgen-dependent enzymes (chymotrypsin, trypsin and renin) are located in the secretory tubules.

Age Factors↗
PubMed1971

Kallikrein, trypsin-like proteases and amylase in mammalian submaxillary glands.

1. The tissue concentration of kallikrein, trypsin-like proteases and amylase has been determined in the submaxillary glands of the cat, dog, rabbit, rat, hamster and guinea-pig.2. Submaxillary gland extracts of the six species showed a wide variation in kallikrein content. The esterase activity in the extracts, however, did not correlate with the kininogenase activity of kallikrein. Both activities in each of the six species were affected by proteinase inhibitors but not in the same way.3. Evidence is presented which indicates that trypsin-like proteases similar to those described in the rat, also occur in the hamster and cat submaxillary glands.4. An even greater spread of amylase activity was observed between the species.5. The assumption that mammalian submaxillary kallikreins are identical proteins is questioned.

Amylases↗
PubMed1971

The intracellular localization of kallikrein, trypsin and amylase in dog pancreas.

1. Subcellular organelles containing kallikrein (-ogen), trypsinogen and amylase have been isolated from homogenates of dog pancreas and found on discontinuous sucrose density-gradients to equilibrate with 1.7-1.775 M sucrose.2. The electron microscopic appearance of the isolated enzyme-containing organelles appeared to be identical with that of the secretory (zymogen) granules seen in situ in the acinar cells of the pancreas.3. The sequence of events associated with the storage and intracellular transport of pancreatic secretory enzymes is reviewed. The results obtained in this study have been used to delineate the probable intracellular pathway taken by kallikrein, trypsin and amylase from synthesis to secretion.4. The physiological role of the glandular kallikreins is discussed.

Amylases↗
PubMed1970

Properties of kallikrein-containing granules isolated from the submaxillary gland of the guinea-pig.

1. Granular fractions of high purity consisting of subcellular kallikrein- and amylase-storing organelles have been isolated from homogenates of guinea-pig submaxillary gland.2. The isolated kallikrein- and amylase-containing granules closely resembled secretory granules observed in situ in serous acinar cells in intra-granular appearance, size and histochemical reaction.3. The subcellular, histochemical and ultrastructural studies indicate that the serine protease, kallikrein, is like amylase an exocrine enzyme with a functional role in saliva.

Amylases↗