EXPRESSION OF HUMAN PLACENTAL-LACTOGEN AND VARIANT GROWTH-HORMONE GENES IN PLACENTAS

Previous studies comparing the expression levels of human placental la ctogen (hPL) genes have shown varying results, due to, perhaps, the fa ct that in all of them only one placenta was being analyzed. Here, the expression of hPL and growth hormone variant (hGH-V) genes in fifteen term placentas was comparatively analyzed at the RNA level, using rev erse transcription coupled to polymerase chain reaction (RT-PCR). The abundance of the combined RNA transcripts derived from these genes var ied from one placenta to another. The authors found that hPL-4 transcr ipts were more abundant than those of hPL-3 in most samples (ratios fr om 1:1 to 6:1), transcripts from the putative hPL-1 pseudogene were mo re abundant at the unprocessed stage while those of the hGH-V gene wer e mostly processed. Again, the authors of this study observed wide var iation from placenta to placenta in the abundance of both of these typ es of transcripts. The same was observed when a group of six placentas from abortuses and nine from pregnancies complicated by preclampsia, diabetes and hypertension was studied. The authors conclude that the d isagreeing results reported in the literature which are not in agreeme nt concerning the expression levels of hPL genes could be explained by normal variations of their expression levels among the different plac entas analyzed.