BOTH PITUITARY AND PLACENTAL GROWTH-HORMONE TRANSCRIPTS ARE EXPRESSEDIN HUMAN PERIPHERAL-BLOOD MONONUCLEAR-CELLS (PBMC)

The hGH-V gene codes for a variant of human pituitary growth hormone ( hGH-N) named placental growth hormone (hPGH). hPGH shares 93% amino ac id identity with hGH-N. Until now the hGH-V gene was considered to be exclusively expressed in human placenta, where it replaces maternal ci rculating hGH-N at the end of pregnancy. In this study we investigated by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis hGH-N, and hGH-V, gene expression in PBMC in men, women and pregnant w omen, We have demonstrated that hGH-N and hGH-V transcripts are simult aneously produced by PBMC in both men and women as well as pregnant wo men. The PBMC of a PIT-1-negative woman expressed only the hGH-V trans cript, but not the hGH-N one as expected. In conclusion, hGH-V mRNA is expressed by cells other than the syncytiotrophoblast, is not regulat ed by PIT-I, and may be involved in immune regulation, as is pituitary GH.