Chemical Composition of Basophil Granules from Isolated Rat Mast Cells

Bergqvist, Ulla; Samuelsson, Gunnar; Uvnäs, Börje

doi:10.1111/j.1748-1716.1971.tb05089.x

Cited by 52 publications

(25 citation statements)

References 33 publications

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“…Our findings also do not clearly indicate a role for MCs in HA metabolism. The presence of t-MH in MCs may be due to the relatively non-selective ion exchange properties of sulfomucopolysaccharides in MC granules [21,23]. Since MCs contain so little t-MH relative to HA, t-MH measurements may be useful in characterizing non-MC stores of HA in tissues like brain.…”

Section: Discussionmentioning

confidence: 98%

Presence and measurement oftele-methylhistamine in mast cells

1984

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The histamine metabolite tele-methylhistamine (t-MH) was identified and measured in crude and purified peritoneal mast cells (MCs). Peritoneal dialysates, peritoneal cells, and purified MCs all contained t-MH in concentrations representing about 0.2% of the corresponding histamine (HA) levels. T-MH levels in crude cells represented about 70% of the total dialysate levels, indicating the presence of extracellular as well as intracellular t-MH. T-MH levels per MC in purified fractions were similar to those of crude fractions, indicating a MC origin for the intracellular t-MH. Histamine methyltransferase activity was not detected in crude or purified MC fractions, and incubations with the monoamine oxidase inhibitor pargyline failed to increase the content or release of t-MH in either fraction, suggesting a very slow or non-existent histamine methylation in MCs. Compound 48/80 produced a temperature-dependent release of HA and t-MH in crude and purified preparations, and Triton X-100 also released both amines. In all cases, the degree of release of both amines was correlated, consistent with a granular origin for t-MH in MCs. The low concentrations of t-MH in MCs do not necessarily indicate a role for MCs in HA metabolism, but suggest that t-MH may be a valuable marker for non-MC HA.

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Section: Discussionmentioning

confidence: 98%

Presence and measurement oftele-methylhistamine in mast cells

1984

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“…In order to get some indirect information on the mechanisms of intragranular hormone storage, L T H granules were submitted to a number of treatments, most of which are known to severely damage isolated organelles (20)(21)(22)(23)(24)(25). For convenience, many of these experiments were carried out with crude granule preparations; however, with purified granules similar results were obtained.…”

Section: Resultsmentioning

confidence: 99%

“…In fact, (a) isolated LTH granules are apparently unaffected by a number of treatments which are known to solubilize secretory granules derived from different sources (19)(20)(21)(22)(23)(24)(25), and (b) such unusual resistance is primarily dependent on the organization of the granule content, since it is little changed after removal of the limiting membrane of the organelle: Only in relation to the pH of the suspending medium did the behavior of membraneless and intact granules prove to be different: intact granules are stable upon incubation at pH 7.4 and only a small proportion of them is solubilized at pH 8.5, whereas membraneless granules are much more fragile. This phenomenon might have a physiological significance in relation to the mechanism by which the LTH granules released by exocytosis are solubilized in the slightly alkaline environment of the extracellular space.…”

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confidence: 99%

Molecular organization of rat prolactin granules: in vitro stability of intact and "membraneless" granules

Giannattasio¹,

Zanini²,

Meldolesi³

1975

The Journal of Cell Biology

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Studies carried out on a number of secretory cell systems suggest that the specific cytoplasmic granules in which the secretion products are stored before their release are complex organelles which can possess a distinct molecular organization. For instance, it has been reported that in some granules the segregated secretion products are organized into crystalline structures (1-3) or large intermolecular aggregates (4-8). It is likely that all phenomena of this type are favorable to the economy of the cell, in the sense that they reduce the energy required for storage of the secretion products. The prolactin (LTH) granules of the rat pituitary possess a number of morphological features which strongly suggest that the molecules(s) of their content might be arranged in a relatively stable structure. Thus, these granules are remarkably polymorphic in shape, and their membrane is usually separated from their content by a clear space. Furthermore, identifiable LTH granules devoid of their membrane are often seen in the pericapillary space, suggesting that upon discharge by exocytosis they are dissolved only slowly (9). However, no studies specifically concerned with the mechanisms of LTH storage have been reported so far. In order to obtain some information on this question, we have studied the behavior of isolated granule fractions incubated in vitro under a variety of carefully controlled experimental conditions.

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“…Hence, the only acid mucopolysaccharide (AMPS) of the MC granules is heparin [Serafini-F racassini et al, 1969;Uvnas et al, 1970: Butler, 1971: Bergqvist et al, 1971, although H orsfield [ 1966] claims there is another AMPS which is com pletely removed by em bedding in paraffin. In the present experim ent MCs preserved by any of the techniques were inetaclirom atic as well as PAS-positive.…”

Section: Discussionmentioning

confidence: 99%