title: Effects of extra- and intracellular calcium concentration on DNA replication, lateral growth, and differentiation of human epidermal cells in culture.
abstract: Variation in the extra- and intra-cellular concentration of calcium ([Ca]e and [Ca]i) affected the 3H-thymidine labeling pattern of sorted S-phase cells in human epidermal cultures. A lowering of [Ca]e resulted in retarded lateral growth but, unless [Ca]e was extremely low, caused an increase in the proportion of strongly labelled (rapidly cycling) S-phase cells. An increased desquamation of superficial cells due to a reduced cellular cohesiveness was also observed in low calcium medium. Thus, a lowering of [Ca]e might stimulate the proliferation of a pool of cycling cells destined for rapid terminal differentiation and tissue regeneration, whereas proliferation destined for lateral growth is inhibited. Attempts to decrease the [Ca]i with the calcium chelator quin-2 at low [Ca]e seemed to elevate the proportion of strongly labelled S-phase cells, whereas an increased [Ca]i obtained with the ionophore A23187 caused a dramatic decrease in the proportion of S-phase cells that showed strong 3H-thymidine incorporation. This implies that variation in both [Ca]i and [Ca]e may play a role in the regulation of proliferation and differentiation, in keratinocytes.
authors.affiliation: Institute of Human Genetics, University of Aarhus, Denmark.
authors.forename: P K
authors.initials: PK
authors.lastname: Jensen
authors.forename: J O
authors.initials: JO
authors.lastname: Nørgård
authors.forename: C
authors.initials: C
authors.lastname: Knudsen
authors.forename: V
authors.initials: V
authors.lastname: Nielsen
authors.forename: L
authors.initials: L
authors.lastname: Bolund
mesh_terms: D000634:Aminoquinolines / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002454:Cell Differentiation; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism* / Q000648:ultrastructure; D004261:DNA Replication; D004533:Egtazic Acid / Q000494:pharmacology; D004817:Epidermis / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D005434:Flow Cytometry; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D007700:Kinetics; D013936:Thymidine / Q000378:metabolism
chemical_list: D000634:Aminoquinolines; D000001:Calcimycin; D004533:Egtazic Acid; D004247:DNA; C035739:Quin2; D002118:Calcium; D013936:Thymidine