Multihormonal Regulation of Thyroglobulin Production by the OVNIS 6H Thyroid Cell Line

Abstract

The hormonal regulation of thyroglobulin production has been studied using a clone of the ovine thyroid cell line: OVNIS 6H. 3 among the 6 hormones proposed for serum replacement are required for an optimal thyroglobulin production; insulin, hydrocortisone and thyrotropin. Insulin alone stimulates thyroglobulin production. The presence of insulin is also required to observe hydrocortisone and TSH stimulations. Newborn calf serum inhibits thyroglobulin production. The best conditions for optimal thyroglobulin expression and TSH responsiveness are obtained in serum-free medium supplemented with 5 micrograms/ml insulin, 100 nM hydrocortisone and 1 mU/ml TSH.

Hormonal regulation of some steps of thyroglobulin synthesis and secretion in bicameral cell culture

“…This observation correlated well with the increase of total RNA as indicated above. The 5H medium with or without TSH increased total RNA, Tg mRNA, and the amount of Tg secreted into the apical medium as insulin did, suggesting that, in this mixture, insulin and hydrocortisone modulated Tg synthesis and that the other components (transferrin, somatostatin and glycyl-2-histidyl-1-lysine acetate) did not play a part in Tg gene expression, as reported by Aouani et al (1988).…”

“…This observation suggests that insulin and hydrocortisone added together lead to an amplified TSH effect. Aouani et al (1988) observed a permissive effect of insulin and hydrocortisone when they studied multihormonal regulation of Tg secreted by the OVNIS cell line. In our culture system, we evidenced a direct effect of insulin and TSH on the amount of Tg secreted into the apical medium; however we observed an amplified effect when TSH, insulin, and hydrocortisone were added together to the basal medium, suggesting that a permissive effect appeared when the three hormones together controlled Tg synthesis and secretion.…”

“…A complementary regulation of Tg mRNA level and synthesis by other hor-0 1994 WLEY-LISS, INC. mones (particularly by insulin and hydrocortisone) has been demonstrated on primary cultures and cell lines. The influence of insulin on transcription (Santisteban et al, 1987;Gerard et al, 1989;Zarrilli et al, 1990), and its effect on Tg accumulation in the culture medium was demonstrated in different systems (Santisteban et al, 1987;Aouani et al, 1988). The implication of hydrocortisone was also evidenced (Aouani et al, 1988).…”

“…The influence of insulin on transcription (Santisteban et al, 1987;Gerard et al, 1989;Zarrilli et al, 1990), and its effect on Tg accumulation in the culture medium was demonstrated in different systems (Santisteban et al, 1987;Aouani et al, 1988). The implication of hydrocortisone was also evidenced (Aouani et al, 1988). The difficulty with such studies is to determine in which proportion each hormone truly stimulates when several hormones are involved.…”

Physiological and pathological regulation of thyroid cell proliferation and differentiation by thyrotropin and other factors

“…In some species,such as sheep and calf, hydrocortisone potentiates this differentiating effect (10,110). These effects are obtained in all the cells of a culture, as shown by in situ hybridization experiments (250).…”