Prostatic androgen repressed message-1 (PARM-1) may play a role in prostatic cell immortalisation.

BACKGROUND: Prostatic androgen-repressed message-1 (PARM-1) has been cloned from the prostate. The transcript of the PARM-1 gene is overexpressed during regression of the prostate after androgen withdrawal. The regulation of PARM-1 by androgens is limited to this organ. We have studied the effects of PARM-1 overexpression in malignant prostate cells. METHODS: The PARM-1 cDNA was introduced into the rat cancer cell line MAT LyLu along with a doxycycline-dependent regulator. RESULTS: Maximal expression of PARM-1 (fivefold induction) was achieved by incubating the cells with 2 microM doxycycline for 48 hr. A study investigating the effect of PARM-1 overexpression on the transcription of 588 genes has shown that the TLP1 gene (encoding rat telomerase protein component 1) was the most up-regulated (fourfold). In addition, a dose-dependent increase in telomerase activity was observed in cells overexpressing PARM-1. In vivo, the androgen-deprived prostate showed an increased TLP1 level and increased telomerase activity. CONCLUSIONS: Increased telomerase activity is often associated with the immortalisation of cancer cell lines, particularly prostatic ones. This could mean that PARM-1 is involved, via increased telomerase activity, in a survival program enabling certain prostatic cells to resist apoptosis, thus conferring a selective advantage to pre-cancerous or cancerous cells.

Placental GH, IGF-I, IGF-binding protein-1, and leptin during a glucose challenge test in pregnant women: relation with maternal body weight, glucose tolerance, and birth weight.

The prediction of birth weight may be improved by the measurement of hormones or growth factors in the mother. We measured body weight (BW) and plasma levels of placental GH (PGH), IGF-I, IGF-binding protein-1 (IGFBP-1), and leptin at the time of the glucose challenge test (GCT) in 289 women, who were pregnant with a single fetus, between 24 and 29 wk gestational age (GA). Delivery occurred 12 +/- 2 (mean +/- SD) wk later. First, we examined which variables regulate these hormonal factors. Multiple regression showed that PGH concentrations were determined by GA at sampling and were negatively related to BW. IGF-I levels were mainly determined by PGH, and also by insulin, BW, and (negatively) age. IGFBP-1 concentrations were negatively determined by BW, insulin, and IGF-I. BW was also a powerful determinant of leptin levels, with insulin as a less robust determinant. Second, we examined the relation to glucose levels. PGH, IGF-I, and IGFBP-1 concentrations were not correlated with post-GCT glucose levels and were comparable in women with a normal or disturbed GCT (glucose >/=7.8 mmol/liter; n = 72). Finally, we examined the relation with birth weight and placental weight. Birth weight, corrected for GA and stratified into percentile groups, and the ponderal index at birth were strongly related to maternal BW, but not to maternal PGH, IGF-I, or IGFBP-1 levels. Neither was maternal leptin related to birth weight, but leptin concentrations were slightly higher in women who delivered obese babies. Placental weight was not related to any of the hormonal factors. This prospective study indicates that the variation in circulating PGH, IGF-I, IGFBP-1, and leptin between 24 and 29 wk of pregnancy is strongly dependent on maternal BW, but is unrelated to glucose tolerance. In addition, the measurement of PGH, IGF-I, IGFBP-1, or leptin at the time of the GCT is not useful clinically to predict birth weight.