IDENTIFICATION BY HYBRIDIZATION HISTOCHEMISTRY OF HUMAN ENDOMETRIAL CELLS EXPRESSING MESSENGER-RNAS ENCODING A UTERINE BETA-LACTOGLOBULIN HOMOLOG AND INSULIN-LIKE GROWTH FACTOR-BINDING PROTEIN-1

A β-lactoglobulin homologue (βLG/PP14) and insulin-like growth factor-binding protein-1 (IGFBP-1) are two major secretory proteins of the human endometrium. In the present study, we have shown that βLG/PP14 mRNA is expressed in the endometrium in a cyclic manner, being hardly detectable in midcycle and most abundant during the late secretory phase. IGFBP-1 mRNA is also expressed in endometrium, but in amounts smaller than those encoding βLG/PP14 and with maximal accumulation earlier in the secretory phase. The expression of these two mRNAs occurs in different cell types of the endometrium, as revealed by in situ hybridization techniques using single-stranded RNA probes. The glandular epithelial cells accumulate βLG/PP14 mRNA during the late secretory phase of the cycle, whereas only the stromal cells of the late secretory endometrium express IGFBP-1 mRNA. In contrast to the endometrium, the two mRNAs are present at very low abundance in the fallopian tubes where they are expressed in the epithelial cells of the mucosa. © 1990 by The Endocrine Society.