Potassium transport and content during G1 and S phase following serum stimulation of 3T3 cells

J. T. Tupper, F. Zorgniotti, B. Mills

Research output: Contribution to journalArticle

79 Citations (Scopus)

Abstract

The effect of serum stimulation on unidirectional and net K flux and their relationship to the initiation of DNA synthesis has been investigated in mouse 3T3 fibroblasts. Stimulation of quiescent 3T3 cells with 20% serum results in the initiation of S phase approximately ten hours after serum addition. During transition from G1 to S phase distinct changes in K transport and cellular K content occur. Total unidirectional K influx undergoes an immediate 2 fold increase upon serum addition, an observation in qualitative agreement with previous results (Rozengurt and Heppel, '75). This total increase in unidirectional K influx represents a proportional increase in the active, ouabain sensitive component and the KK exchange component. The initial increase in total flux is followed by a gradual decline over a 16 hour period to levels approaching those of quiescent cells. Following the initial increase in unidirectional K influx is an approximately 75% increase in cell K on a per milligram protein basis or a 40% increase on a per volume basis. This increase peaks at four to five hours and then declines to initial levels at 10 to 14 hours. Populations of quiescent cells given 20% serum plus 0.5 mM ouabain simultaneously are totally blocked from entering S phase, as determined by the appearance of 3H thymidine labeled nuclei. However, if the oubain is removed after six hours these cells then undergo the same changes in unidirectional K influx and content as serum stimulated cells with entrance into S phase retarded by five to six hours. If ouabain is added to serum stimulated cells at six hours, after the increase in K tansport and K content have occurred, entrance into S phase is not entirely blocked. If cells stimulated with serum and 0.5 mM dBcAMP plus 1 mM theophylline simultaneously, entrance into S phase is greatly reduced as compared to serum stimulation only. However, the early and late changes in K flux and K content are not substantially altered. This indicates that the K transport events associated with G1 and early S phase are not directly regulated by changes in cAMP levels which follow serum stimulation.

Original languageEnglish (US)
Pages (from-to)429-440
Number of pages12
JournalJournal of Cellular Physiology
Volume91
Issue number3
StatePublished - 1977

Fingerprint

3T3 Cells
G1 Phase
Ouabain
S Phase
Potassium
Fluxes
Serum
Fibroblasts
Theophylline
Thymidine
Cells
DNA
Proteins
Observation

ASJC Scopus subject areas

  • Cell Biology
  • Clinical Biochemistry
  • Physiology

Cite this

Potassium transport and content during G1 and S phase following serum stimulation of 3T3 cells. / Tupper, J. T.; Zorgniotti, F.; Mills, B.

In: Journal of Cellular Physiology, Vol. 91, No. 3, 1977, p. 429-440.

Research output: Contribution to journalArticle

Tupper, J. T. ; Zorgniotti, F. ; Mills, B. / Potassium transport and content during G1 and S phase following serum stimulation of 3T3 cells. In: Journal of Cellular Physiology. 1977 ; Vol. 91, No. 3. pp. 429-440.
@article{3664019e922e4c049f2735eba4f658ad,
title = "Potassium transport and content during G1 and S phase following serum stimulation of 3T3 cells",
abstract = "The effect of serum stimulation on unidirectional and net K flux and their relationship to the initiation of DNA synthesis has been investigated in mouse 3T3 fibroblasts. Stimulation of quiescent 3T3 cells with 20{\%} serum results in the initiation of S phase approximately ten hours after serum addition. During transition from G1 to S phase distinct changes in K transport and cellular K content occur. Total unidirectional K influx undergoes an immediate 2 fold increase upon serum addition, an observation in qualitative agreement with previous results (Rozengurt and Heppel, '75). This total increase in unidirectional K influx represents a proportional increase in the active, ouabain sensitive component and the KK exchange component. The initial increase in total flux is followed by a gradual decline over a 16 hour period to levels approaching those of quiescent cells. Following the initial increase in unidirectional K influx is an approximately 75{\%} increase in cell K on a per milligram protein basis or a 40{\%} increase on a per volume basis. This increase peaks at four to five hours and then declines to initial levels at 10 to 14 hours. Populations of quiescent cells given 20{\%} serum plus 0.5 mM ouabain simultaneously are totally blocked from entering S phase, as determined by the appearance of 3H thymidine labeled nuclei. However, if the oubain is removed after six hours these cells then undergo the same changes in unidirectional K influx and content as serum stimulated cells with entrance into S phase retarded by five to six hours. If ouabain is added to serum stimulated cells at six hours, after the increase in K tansport and K content have occurred, entrance into S phase is not entirely blocked. If cells stimulated with serum and 0.5 mM dBcAMP plus 1 mM theophylline simultaneously, entrance into S phase is greatly reduced as compared to serum stimulation only. However, the early and late changes in K flux and K content are not substantially altered. This indicates that the K transport events associated with G1 and early S phase are not directly regulated by changes in cAMP levels which follow serum stimulation.",
author = "Tupper, {J. T.} and F. Zorgniotti and B. Mills",
year = "1977",
language = "English (US)",
volume = "91",
pages = "429--440",
journal = "Journal of Cellular Physiology",
issn = "0021-9541",
publisher = "Wiley-Liss Inc.",
number = "3",

}

TY - JOUR

T1 - Potassium transport and content during G1 and S phase following serum stimulation of 3T3 cells

AU - Tupper, J. T.

AU - Zorgniotti, F.

AU - Mills, B.

PY - 1977

Y1 - 1977

N2 - The effect of serum stimulation on unidirectional and net K flux and their relationship to the initiation of DNA synthesis has been investigated in mouse 3T3 fibroblasts. Stimulation of quiescent 3T3 cells with 20% serum results in the initiation of S phase approximately ten hours after serum addition. During transition from G1 to S phase distinct changes in K transport and cellular K content occur. Total unidirectional K influx undergoes an immediate 2 fold increase upon serum addition, an observation in qualitative agreement with previous results (Rozengurt and Heppel, '75). This total increase in unidirectional K influx represents a proportional increase in the active, ouabain sensitive component and the KK exchange component. The initial increase in total flux is followed by a gradual decline over a 16 hour period to levels approaching those of quiescent cells. Following the initial increase in unidirectional K influx is an approximately 75% increase in cell K on a per milligram protein basis or a 40% increase on a per volume basis. This increase peaks at four to five hours and then declines to initial levels at 10 to 14 hours. Populations of quiescent cells given 20% serum plus 0.5 mM ouabain simultaneously are totally blocked from entering S phase, as determined by the appearance of 3H thymidine labeled nuclei. However, if the oubain is removed after six hours these cells then undergo the same changes in unidirectional K influx and content as serum stimulated cells with entrance into S phase retarded by five to six hours. If ouabain is added to serum stimulated cells at six hours, after the increase in K tansport and K content have occurred, entrance into S phase is not entirely blocked. If cells stimulated with serum and 0.5 mM dBcAMP plus 1 mM theophylline simultaneously, entrance into S phase is greatly reduced as compared to serum stimulation only. However, the early and late changes in K flux and K content are not substantially altered. This indicates that the K transport events associated with G1 and early S phase are not directly regulated by changes in cAMP levels which follow serum stimulation.

AB - The effect of serum stimulation on unidirectional and net K flux and their relationship to the initiation of DNA synthesis has been investigated in mouse 3T3 fibroblasts. Stimulation of quiescent 3T3 cells with 20% serum results in the initiation of S phase approximately ten hours after serum addition. During transition from G1 to S phase distinct changes in K transport and cellular K content occur. Total unidirectional K influx undergoes an immediate 2 fold increase upon serum addition, an observation in qualitative agreement with previous results (Rozengurt and Heppel, '75). This total increase in unidirectional K influx represents a proportional increase in the active, ouabain sensitive component and the KK exchange component. The initial increase in total flux is followed by a gradual decline over a 16 hour period to levels approaching those of quiescent cells. Following the initial increase in unidirectional K influx is an approximately 75% increase in cell K on a per milligram protein basis or a 40% increase on a per volume basis. This increase peaks at four to five hours and then declines to initial levels at 10 to 14 hours. Populations of quiescent cells given 20% serum plus 0.5 mM ouabain simultaneously are totally blocked from entering S phase, as determined by the appearance of 3H thymidine labeled nuclei. However, if the oubain is removed after six hours these cells then undergo the same changes in unidirectional K influx and content as serum stimulated cells with entrance into S phase retarded by five to six hours. If ouabain is added to serum stimulated cells at six hours, after the increase in K tansport and K content have occurred, entrance into S phase is not entirely blocked. If cells stimulated with serum and 0.5 mM dBcAMP plus 1 mM theophylline simultaneously, entrance into S phase is greatly reduced as compared to serum stimulation only. However, the early and late changes in K flux and K content are not substantially altered. This indicates that the K transport events associated with G1 and early S phase are not directly regulated by changes in cAMP levels which follow serum stimulation.

UR - http://www.scopus.com/inward/record.url?scp=0017377375&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0017377375&partnerID=8YFLogxK

M3 - Article

VL - 91

SP - 429

EP - 440

JO - Journal of Cellular Physiology

JF - Journal of Cellular Physiology

SN - 0021-9541

IS - 3

ER -