Polarity of three-dimensional structures derived from isolated hog thyroid cells in primary culture

Abstract

When cultured in polystyrene dishes subjected to previous treatment and supplied with a serum-containing medium, hog thyroid cells form monolayers displaying dome-like arrangements after three to four days. Cells involved in formation of "domes" are morphologically polarized; the apical microvilli of these cells point toward the culture medium. When the tissue is cultured in untreated polystyrene dishes, thyroid cells remain in suspension; their aggregates swell progressively and form hollow spheres encompassed by a single layer of cells. The polarity of the cells forming such spheres is inverse in comparison to the condition characteristic of the intact thyroid gland. When culture medium is supplemented with TSH, PGE1, PGE2 or dBC, structures resembling true follicles are formed in both types of cultures. Gelatin, added to suspension cultures, is also capable of promoting follicle formation. Cultured thyroid cells regularly form an epithelial layer as a result of the interaction of cellular processes. However, the polarization of this layer depends on culture conditions. Thus, structures with either a normal follicle-like polarization of their cells or showing an inverted type of polarization can be obtained.

Modulation of adenylate cyclase activity by thyrotropin in cultured thyroid cells

“…Cells were isolated from thyroid glands of adult hogs by a modified [6] discontinuous trypsinization procedure [7]. The Eagle minimum essential medium used was buffered at pH 7.4 and supplemented with 10% newborn calf serum and contained 200 units/ml penicillin, 50 pU/ml streptomycine sulfate and 0.25% (w/v) gelatin [8].…”

“…Preliminary experiments showed that the factor present in the supematant was heat stable and dialyzab~e. Thus the increased responsiveness of the adenyiate cyclase system to TSH (positive regulation) observed when thyroid cells are cultured with O-100 @J/ml TSH ( [2,3], table 1) might be associated with modulation of the intrace~u~r GTP level by the hormone. An estimate of -1 mM for the intracellular GTP concentration in TSH-treated cells can be derived from data of the type described in table 2 if we assume that the concentration of free GTP in the homogenate is 10 PM on the basis of the identical effect obtained on TSH striation of the 104 X g fraction by addition of the lo5 X g supernatant or 10 ,uM GTP and using 4 pl/mg protein for the cell volume [ 151.…”

Specific inhibition by Na+ of TSH‐stimulated thyroid cell adenylate cyclase

“…In addition to its action on the inhibition of cAMP synthesis by adrenergic [9], muscarinic cholinergic agonists [6][7][8][9][10][11][12][13] and opiates [6,14] Na ÷ appears to have divergent effects on adenylate cyclase activities depending on the biological system studied. In the porcine kidney medulla, Na ÷ was required for full expression of stimulation by vasopressin [8].…”

“…Thyroid epithelial cells were obtained from porcine thyroid glands by a discontinuous trypsin-EGTA treatment [11 ]. Freshly isolated ceils were suspended at 2 X 106 cells/ml in Eagle minimum essential medium supplemented with newborn calf serum (10%, v/v), gelatin (0.25%) and TSH (0.1 mU/ml) unless otherwise mentioned.…”

“…Cells were incubated for 4 days as unstirred suspension in untreated polystyrene dishes (10 ml cell suspension/100 mm dishes) in 95% air/5% CO2 water-saturated atmosphere at 37°C. Under these conditions cells reorganized into follicles and displayed maximal responsiveness to acute TSH stimulation [1,11].…”