A progestin effect on lactate dehydrogenase in the human breast cancer cell line T-47D.

The human breast cancer cell line T-47D has high levels of progesterone receptor even in the absence of exogenously added estrogen. Because of this it is a good line in which to study aspects of progestin action. It has been shown by others that lactate dehydrogenase in MCF-7 cells is responsive to estrogen but not to progesterone. Other proteins in other systems have been found to be responsive to both estrogen and progesterone, often requiring priming by estrogen, presumably to produce sufficiently high quantities of progesterone receptor. Reasoning that lactate dehydrogenase in T-47D cells might be stimulated by progestins alone at physiological levels since these cells already have high levels of progesterone receptor, we now report that this is indeed the case.