TRIIODOTHYRONINE AND FOLLICLE-STIMULATING-HORMONE, ALONE AND ADDITIVELY TOGETHER, STIMULATE PRODUCTION OF THE TISSUE INHIBITOR OF METALLOPROTEINASES-1 IN CULTURED HUMAN LUTEINIZED GRANULOSA-CELLS

Thyroid disorders have been frequently associated with menstrual distu rbances and impaired fertility. To characterize the nature of thyroid hormone action in the ovary, the direct effects of T-3-gonadotropin in teractions were investigated in vitro using a culture system of human luteinized granulosa cells in serum-free medium. Although FSH alone wa s devoid of any significant effect on cell proliferation, it inhibited T-3-stimulated cell growth. The electrophoretic profiles of the radio labeled proteins induced by the different hormonal treatments revealed similarity in overall protein patterns but differences in intensity o f labeling. Human CG, alone or combined with T-3, had no major influen ce on the total intensity of labeling compared with control, whereas T -3 or FSH alone reduced total labeling intensity but a 30,000 Da prote in band was increased. FSH combined with T-3 augmented the total inten sity of labeling, including the 30,000-Da protein band. Western blot a nalysis revealed the presence of the tissue inhibitor of metalloprotei nases-1 (TIMP-1), mol wt 30,000, known to play a key role in ovarian f unction. TIMP-1 was dose dependently stimulated by T-3 and FSH, and an additive effect was obtained when both hormones were combined. This i s the first report of TIMP-1 modulation by FSH in ovarian cells and of an effect by thyroid hormone on TIMP-1 levels. The study shows TIMP-1 induction in human ovarian cells not only by FSH, i.e. via a probable protein kinase A mechanism, but also demonstrates an additional mode of TIMP-1 hormonal induction: via thyroid hormone stimulation, acting by modulation of gene transcription. The present study provides novel data on TIMP-1 hormonal modulation and of direct T-3 in vitro ovarian effects that may account for the in vivo indications of a thyroid-ovar ian connection.