Spatial and temporal thyrocyte response to TSH: a computer-assisted image analysis.
Pseudopods at the apical pole of porcine thyroid monolayers in culture were considered as reflecting individual thyrocyte responses to thyrotropin (TSH) stimulation. Scanning electron microscopy and computer-assisted image analysis showed that whatever TSH stimulation was used, the pseudopods were characterized by two populations: P1 with small diameters (2 microns) and P2 with greater diameters (5 microns). The density of P1 rapidly increased to reach a plateau, while P2 continuously increased during stimulation. Two-dimensional pseudopod patterns were compared with random point distributions by means of two topographical parameters: the interpseudopod distances and angles. A factorial analysis of experimental distribution of pseudopods obtained after increasing stimulation times displayed a shift from a nonrandom (10-20 min) to a random (60-90 min) distribution. Clusters of three pseudopods characterized by short distances (6-9 microns) and equilateral organization (angles 40-60 degrees) were observed after a 10-min stimulation. These results suggested that early thyrocyte response to TSH stimulation is characterized by interrelations between three adjoining cells, with the thyrocyte response later appearing as random.
Penel
C
C
Faculté de Médecine Nord, Institut National de la Santé et de la Recherche Médicale U270, Marseille, France.
Mauchamp
J
J
D000818:Animals; D002478:Cells, Cultured; D007091:Image Processing, Computer-Assisted; D008855:Microscopy, Electron, Scanning; D013961:Thyroid Gland / Q000166:cytology / Q000187:drug effects* / Q000648:ultrastructure; D013997:Time Factors