neuromedin-c and gastrin-releasing-peptide-(14-27)

Extracts of human term amnion, placenta, and chorion/decidual tissue (n = 5) contained gastrin-releasing peptide-like immunoreactivity (GRPLI) in amounts of 4.7 +/- 2.9 (pmol/g wet wt; mean +/- SEM), 3.6 +/- 1.1 and 2.9 +/- 1.5, respectively. Using C-terminally directed antisera and gel filtration chromatography and reverse-phase high-performance liquid chromatography (HPLC), each tissue contained molecular forms consistent with the presence of GRP1-27 and GRP18-27 but also contained larger amounts of two GRPLI peaks, which apparently are novel GRP-like peptides. In contrast, tissue extracts of human fetal lung contained only GRP1-27, GRP14-27, and GRP18-27. Using RT-PCR and specific GRP primers and probes, messenger RNA encoding for GRP was readily demonstrable from 6-weeks gestation throughout pregnancy to term in full-thickness membranes, placental villi, and decidua. Positive immunohistochemical staining for GRP occurred in extravillous trophoblasts in decidual septa and fetal membranes, cytotrophoblasts, syncytiotrophoblast, and certain stromal cells in placental villi and amniotic epithelium. GRPLI and GRP messenger RNA were present from the earliest dates examined (6-9 weeks) throughout pregnancy to term. Given the proven trophic nature of GRP and related peptides, these peptides may play important roles in maternal, placental, and fetal development during human pregnancy.

Topics: Amnion; Bombesin; Chorion; Chromatography, Gel; Chromatography, High Pressure Liquid; Decidua; DNA Primers; Female; Gastrin-Releasing Peptide; Humans; Immunohistochemistry; Peptide Fragments; Peptides; Placenta; Polymerase Chain Reaction; Pregnancy; Radioimmunoassay; RNA-Directed DNA Polymerase; RNA, Messenger

The production and postsecretory stability of gastrin-releasing peptide (GRP) and the C-terminal part of the GRP precursor were studied in small cell lung cancer cell lines using RIAs developed against these two parts of the precursor. In three otherwise different cell lines (NIC-H345, NIC-H69, and NIC-H510), similar chromatographic patterns of mainly GRP-(18-27) and some GRP-(14-27) along with large fragments of the C-terminal counterpart of the precursor were found to be stored in the cells. In tissue culture medium, gel filtration chromatography indicated that postsecretory limited proteolysis of the GRP precursor fragments occurred. The amount of accumulated immunoreactivity varied among the three cell lines and between the two parts of the precursor. In medium in which only low amounts of GRP immunoreactivity accumulated, the radiolabeled GRP was degraded rapidly. When incubated with plasma, GRP-(14-27) disappeared within a few hours, whereas the C-terminal precursor fragments were stable. It is concluded that the postsecretory stability of peptides excised from the GRP precursor in small cell lung cancer cells varies under tissue culture conditions, but epitopes in the C-terminal part of the precursor are more stable in plasma than the small GRP peptides and, thus, may serve as a better indicator than GRP itself for expression of the GRP precursor in cancer cells.

Topics: Amino Acid Sequence; Biomarkers, Tumor; Bombesin; Carcinoma, Small Cell; Cell Line; Chromatography, Gel; Chromatography, High Pressure Liquid; Chromosome Mapping; Gastrin-Releasing Peptide; Gene Expression; Humans; Immunoradiometric Assay; In Vitro Techniques; Lung Neoplasms; Molecular Sequence Data; Peptide Fragments; Peptides; Sequence Homology, Nucleic Acid; Substance P

Purified adult rat Leydig cells were found to produce gastrin-releasing peptide (GRP) by radioimmunoassay (RIA). Gel chromatography of the extracted material showed a single peak of GRP immunoreactivity. Further high pressure liquid chromatography (HPLC) analysis resolved the extract into two peaks that closely resembled the C-terminal fragment of GRP, GRP18-27 and GRP14-27. Immunohistochemical studies revealed specific staining for GRP in the Leydig cells of adult rat testis. These results demonstrate, by a number of independent criteria, that rat Leydig cells contain substances which behave like authentic GRP-like peptides. Since the peptides appear to be of local origin, a paracrine function within the rat testis is suggested.

Topics: Animals; Bombesin; Chromatography, Gel; Chromatography, High Pressure Liquid; Gastrin-Releasing Peptide; Immunoenzyme Techniques; Leydig Cells; Male; Peptide Fragments; Peptides; Radioimmunoassay; Rats; Rats, Inbred Strains