Search Results

You are looking at 1 - 2 of 2 items for

  • Author: C C Sijmons x
  • Refine by Access: All content x
Clear All Modify Search
Restricted access

M T den Hartog, C C Sijmons, P M P Kristel, O Bakker, and J J M de Vijlder


The synthesis is described of an N-terminal thyroglobulin (Tg) polypeptide of 27 kDa, which is capable of hormonogenesis, in a baculovirus system. This polypeptide was made using a 657 bp Tg cDNA cloned from human thyroid RNA by a polymerase chain reaction method. The cDNA contained the information for the Tg signal peptide, the N-terminally located site for thyroid hormone formation and, at the 3′ end, a sequence coding for six histidine residues. The fragments produced were purified using a nickel—nitrilotriacetic acid column using these six histidine residues. The products were analysed by sodium dodecyl sulphatepolyacrylamide gel electrophoresis and showed two glycosylated fragments of 32 and 34 kDa, both of which started with asparagine. Iodination of the fragments with lactoperoxidase in vitro resulted in the formation of thyroxine (T4). The formation rate of T4 in the fragments was about five times lower than that of the mature Tg dimer of 660 kDa, but ten times more rapid than in bovine serum albumin under the same conditions.

Free access

P Hanifi-Moghaddam, B Sijmons, M C Ott, W F J van IJcken, D Nowzari, E C M Kuhne, P van der Spek, H J Kloosterboer, C W Burger, and L J Blok

Tibolone, a steroidogenic compound with both estrogenic and progestagenic properties, is used as an alternative for estrogen or estrogen plus progesterone hormone therapy for the treatment of symptoms associated with menopause and osteoporosis. We have evaluated whether the effect of tibolone on a human endometrial cell line is similar to, or comparable with, the effect of estradiol (E2), medroxyprogesterone acetate (MPA) or E2 + MPA treatment. Using stable transfection techniques, the estrogen receptor (ER) expressing human endometrial cancer cell line, ECC1, was altered to also express both progesterone receptors (PRs). These cells were then used to assess growth regulation and expression profiling (Affymetrix U133plus2) under the influence of E2 (1 nM), MPA (1 nM), E2 + MPA or tibolone (100 nM). Growth assessment and comparison of profiles indicate that tibolone behaves predominantly like MPA. Furthermore, regulation of prereplication complex genes, such as the minichromosome maintenance genes, could be involved in the observed strong inhibition of growth by tibolone as well as MPA. In addition, in total, 15 genes were found to be specific for tibolone treatment. These genes were predominantly involved in regulation of the cell cycle and differentiation.