AJP - Endocrinology and Metabolism, Vol 263, Issue 2 E231-E238, Copyright © 1992 by American Physiological Society
Spatial and temporal thyrocyte response to TSH: a computer-assisted image analysis
C. Penel and J. Mauchamp
Faculte de Medecine Nord, Institut National de la Sante et de la Recherche Medicale U270, Marseille, France.
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.
