Depletion of L-3,5,3'-Triiodothyronine and L-Thyroxine in Euthyroid Calf Serum for Use in Cell Culture Studies of the Action of Thyroid Hormone*

TLDR

GH1 cells are a clonal rat pituitary tumor cell line that produces growth hormone and prolactin. The study develops an anion‑exchange resin method to remove L‑T3 and L‑T4 from euthyroid calf serum. The resin‑based depletion minimally alters low‑molecular‑weight anions, preserves protein content and electrophoretic patterns, and yields hormone‑depleted serum that elicits the same cellular responses as thyroidectomized serum while maintaining growth‑promoting activity when hormones are restored. This procedure offers a practical alternative to thyroidectomy for preparing thyroid‑hormone‑depleted serum in cell culture studies.

Abstract

GH1 cells are a clonal strain of rat pituitary tumor cells which synthesize GH and PRL. We have previously demonstrated that these cells respond to physiological concentrations of L-T3 and L-T4 when cultured with medium supplemented with thyroidectomized calf serum to achieve a thyroid hormonedepleted state under cell culture conditions. In this study, we describe a method to deplete euthyroid calf serum of L-T3 and L-T4 using an anion exchange resin. We demonstrate that the procedure only minimally alters the low molecular weight anion components of the serum and does not change the total protein content or the electrophoretic pattern of serum proteins. Moreover, we show that euthyroid calf serum depleted of L-T4 and L-T4 by this procedure yields serum which, when used as a medium supplement, results in biological responses identical to those obtained with media supplemented with thyroidectomized calf serum. In addition, resin treatment does not alter the growth-promoting properties of the serum if the thyroid hormone concentration is restored. This procedure should be useful in preparing thyroid hormone-depleted serum for cell culture studies in situations where thyroidectomy is not feasible or would require surgical procedures on a large number of small animals.