Tamoxifen inhibits prolactin signal transduction in ER - NOG-8 mammary epithelial cells.
Das R, Vonderhaar BK.
Laboratory of Tumor Immunology and Biology, National Cancer Institute, Bethesda, MD 20892-1402,
USA.barbarav@helix.nih.gov
Tamoxifen (TAM), an antiestrogen, also acts as an antilactogen in mammary cells. In the present study we analyze the effect of TAM on the signal transduction pathway for prolactin (Prl). TAM bound specifically to NOG-8, an estrogen receptor-negative mammary cell line. Within 5 min of Prl treatment, raf-1, MEK and MAP kinase were induced 2-3-fold over the control level.
TAM completely inhibited this Prl-induced activation of kinases as well as Prl binding and cell growth. These results indicate the potential role of TAM as an antilactogen in Prl responsive systems.
PMID: 9177456 [PubMed - indexed for MEDLINE]
Effectiveness of antiestrogens in infertile men.
Breznik R, Borko E.
Gynecology Department, Maribor Teaching Hospital, Maribor, Slovenia.
Eighty-nine oligozoospermic men, treated by clomiphene or tamoxifen or with no treatment at all, were evaluated during a 4-year follow-up period. Ejaculate volume, sperm concentration, and sperm motility were determined and concentrations of prolactin (PRL), estradiol, beta hCG, prostaglandin E2, zinc, and fructose were ascertained. Isoenzyme LDH-C4 activity and serum PRL and follicle stimulating hormone were also determined. During treatment there was only a minimum increase in sperm concentration. No improvement in sperm motility and no alteration in ejaculate volume were observed. The pregnancy rate was lower in the partners of patients receiving treatment (23.8%) than in the partners of those receiving none (29.6%). Statistically the difference is insignificant.
After antiestrogen therapy, prolactin concentrations in serum decreased and zinc concentrations in seminal plasma increased. For the treatment of idiopathic oligozoospermia in infertile men, clomiphene and tamoxifen were ineffective medication.
Publication Types:
* Clinical Trial
PMID: 8373285 [PubMed - indexed for MEDLINE]