scholarly journals Effects of Xanthine Derivatives on Phosphatidylcholine Secretion in Rat Type II Pneumocytes in the Presence of Activated Eosinophils

1997 ◽  
Vol 75 (4) ◽  
pp. 425-432 ◽  
Author(s):  
Manabu Okumura ◽  
Hirofumi Kai ◽  
Shinya Shinozawa ◽  
Yoichiro Isohama ◽  
Kazuo Takahama ◽  
...  
Keyword(s):  
Type Ii ◽  
Xanthine Derivatives ◽  
Type Ii Pneumocytes ◽  
Phosphatidylcholine Secretion

scholarly journals Effects of Xanthine Derivatives on Phosphatidylcholine Secretion in Primary Culture of Rat Type II Pneumocytes

1995 ◽  
Vol 67 (2) ◽  
pp. 165-168 ◽  
Author(s):  
Manabu Okumura ◽  
Michio Tsuruoka ◽  
Yoichiro Isohama ◽  
Hirofumi Kai ◽  
Kazuo Takahama ◽  
...  
Keyword(s):  
Primary Culture ◽  
Type Ii ◽  
Xanthine Derivatives ◽  
Type Ii Pneumocytes ◽  
Phosphatidylcholine Secretion

Pyridine Derivatives Stimulate Phosphatidylcholine Secretion in Primary Cultures of Rat Type II Pneumocytes

1996 ◽  
Vol 48 (1) ◽  
pp. 53-56 ◽  
Author(s):  
Hirofumi Kai ◽  
Koichiro Murahara ◽  
Yoichiro Isohama ◽  
Kazuo Takahama ◽  
Yoshiaki Oda ◽  
...  
Keyword(s):  
Primary Cultures ◽  
Type Ii ◽  
Pyridine Derivatives ◽  
Type Ii Pneumocytes ◽  
Phosphatidylcholine Secretion

Adrenomedullin increases phosphatidylcholine secretion in rat type II pneumocytes

2000 ◽  
Vol 403 (3) ◽  
pp. 189-194 ◽  
Author(s):  
Manabu Okumura ◽  
Hirofumi Kai ◽  
Kazuhiko Arimori ◽  
Tomomi Iwakiri ◽  
Muneaki Hidaka ◽  
...  
Keyword(s):  
Type Ii ◽  
Type Ii Pneumocytes ◽  
Phosphatidylcholine Secretion

Ontogeny of surfactant secretion in type II pneumocytes from fetal, newborn, and adult rats

1992 ◽  
Vol 262 (3) ◽  
pp. L337-L343 ◽  
Author(s):  
M. Griese ◽  
L. I. Gobran ◽  
S. A. Rooney
Keyword(s):  
Type Ii Cells ◽  
Fetal Life ◽  
Type Ii ◽  
Adult Rats ◽  
Differential Adhesion ◽  
Adenosine A2 Receptor ◽  
Type Ii Pneumocytes ◽  
Fetal Rats ◽  
Surfactant Secretion ◽  
Phosphatidylcholine Secretion

We measured phosphatidylcholine secretion and its response to surfactant secretagogues in type II cells from developing rats. Cells were isolated from fetal rats on day 21 of gestation by digestion with collagenase and trypsin and purification by differential adhesion. Cells were isolated from adult and postnatal rats on days 1, 7, 14, and 30 by elastase digestion and panning on immunoglobulin G-coated dishes. The basal rate of phosphatidylcholine secretion was the same at all ages but there were developmental changes in the response to secretagogues. The response to terbutaline and an adenosine A2 receptor agonist increased from fetal life until day 7 when it reached the level of adult cells. Adenosine deaminase did not increase the response of the cells to these agonists until day 30, suggesting that the adenosine A1 receptor inhibiting secretion does not become functional until that age. The response to 12-O-tetradecanoylphorbol 13-acetate was lower in the fetal cells but had reached the adult level by day 1. The developmental increase in the response of the cells to ATP was more prolonged with the maximum response not being attained until day 30. With the exception of day 30, when the response to most of the secretagogues was very high, the response to ionomycin was the same at the other ages. These data suggest differential maturation of the signal-transduction pathways mediating surfactant secretion in type II cells.

Adenosine A2-receptor-mediated phosphatidylcholine secretion in type II pneumocytes

1991 ◽  
Vol 260 (2) ◽  
pp. L52-L60 ◽  
Author(s):  
M. Griese ◽  
L. I. Gobran ◽  
J. S. Douglas ◽  
S. A. Rooney
Keyword(s):  
Dissociation Constant ◽  
Adenosine Receptor ◽  
Binding Capacity ◽  
Specific Binding ◽  
Physiological Role ◽  
Type Ii Cells ◽  
Type Ii ◽  
Adenosine A2 Receptor ◽  
Type Ii Pneumocytes ◽  
Phosphatidylcholine Secretion

Adenosine and its analogues stimulate phosphatidylcholine secretion in cultured rat type II pneumocytes. There is evidence that this effect is mediated by A2 receptors. We have now employed the radioligand 5'(N-ethylcarboxyamido)adenosine (NECA) in an attempt to study the adenosine receptor in a membrane fraction of type II cells. Specific binding of [3H]-NECA was saturable with a total binding capacity (Bmax) of 4.91 pmol/mg protein and a dissociation constant (Kd) of 240 nM. The Kd was similar to the concentration of NECA which half-maximally stimulated phosphatidylcholine secretion (EC50, 150 nM). Although the relative potency of adenosine analogues in displacing bound [3H]NECA was consistent with that expected at an A2 receptor, there were discrepancies between binding and function with respect to some agonists as well as the antagonist xanthine amine congener (XAC). This together with the unusually high Bmax suggests that the NECA binding site is not the adenosine receptor mediating phosphatidylcholine secretion. The receptor was further characterized functionally by measuring its antagonist dissociation constant (Kb). KbS for XAC inhibition of the effects of NECA, N6-(L-2-phenylisopropyl)adenosine, and adenosine on phosphatidylcholine secretion were 19 +/- 8, 24 +/- 11, and 6 +/- 12 nM, respectively, suggesting that all three agonists act at the same receptor. The Kb value allowed comparison of the receptor in type II cells with that in other tissues and revealed that it was similar to the A2 receptor previously described in human platelets. These functional data further characterize and are consistent with a physiological role for the adenosine A2 receptor in the regulation of lung surfactant secretion.

Secretion of surfactant protein A from rat type II pneumocytes

1993 ◽  
Vol 265 (6) ◽  
pp. L586-L590 ◽  
Author(s):  
S. A. Rooney ◽  
L. I. Gobran ◽  
T. M. Umstead ◽  
D. S. Phelps
Keyword(s):  
Primary Cultures ◽  
Protein A ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Type Ii ◽  
Isolated Cells ◽  
Adult Rats ◽  
Pharmacological Agents ◽  
Type Ii Pneumocytes ◽  
Phosphatidylcholine Secretion

Secretion of surfactant phosphatidylcholine has been extensively studied and there is evidence that it is a regulated process that can be influenced by a variety of physiological factors and pharmacological agents. In contrast, secretion of the major surfactant protein, surfactant protein A (SP-A), has been investigated to much lesser extent. It is not known whether SP-A secretion is constitutive or regulated and, if regulated, whether its regulation is similar to that of phosphatidylcholine. To address those questions we measured SP-A secretion in primary cultures of type II pneumocytes under conditions identical to those used to study phosphatidylcholine secretion. Freshly isolated cells from adult rats were cultured overnight, washed, and then incubated in fresh medium in the presence and absence of surfactant phospholipid secretagogues. As previously reported for phosphatidylcholine, SP-A secretion was linear with time for up to 4 h. However, the rate of SP-A secretion, approximately 6% of total SP-A (cells+medium) released into the medium per hour, was more than sixfold greater than that of the lipid. Although freshly isolated cells contained 70% more SP-A than cells that were cultured overnight, the rate of SP-A secretion was not significantly different. Secretion of SP-A by freshly isolated or cultured type II cells was not increased by a combination of ATP, terbutaline, the adenosine A2 receptor agonist 5'(N-ethylcarboxyamido)adenosine, 12-O-tetradecanoylphorbol-13-acetate, and ionomycin at concentrations that optimally stimulated phosphatidylcholine secretion. We conclude that secretion of the major lipid and protein components of surfactant are independently regulated.

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