title: Identification of prolactin-like proteins synthesized by normal murine lymphocytes.
abstract: Cultured murine lymphoid cells release a PRL-like immunoreactive (IR) protein which may be important in immunity, as anti-PRL antisera inhibit lymphocyte proliferation in vitro. We examined culture supernatants (SNs) and cell lysates from concanavalin A (Con A) activated murine thymocytes to identify these proteins. Western blot analysis of cell lysates revealed three specifically-stained PRL-IRs. A doublet of bands at 35.6 and 33.6 kDa was associated with the particulate fraction of the cell. These PRL-IRs were present in lymphocytes independently of mitogen stimulation. In contrast, a 22 kDa PRL-IR was only produced in mitogen stimulated cells, and was specifically immunoprecipitated with anti-PRL antiserum. In addition, all three PRL-like IRs incorporated 35S-methionine in vitro, indicating that they are synthesized by these cells. Only the 22 kDa PRL-like protein was present in culture medium from stimulated cells, suggesting that this may be the PRL bioactivity previously demonstrated in SNs from murine lymphocytes.
authors.affiliation: Department of Pharmacology, University of Arizona College of Medicine, Tucson 85724.
authors.forename: D W
authors.initials: DW
authors.lastname: Montgomery
authors.forename: J A
authors.initials: JA
authors.lastname: LeFevre
authors.forename: E D
authors.initials: ED
authors.lastname: Ulrich
authors.forename: C R
authors.initials: CR
authors.lastname: Adamson
authors.forename: C F
authors.initials: CF
authors.lastname: Zukoski
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D008214:Lymphocytes / Q000378:metabolism*; D051379:Mice; D011233:Precipitin Tests; D011388:Prolactin / Q000096:biosynthesis*; D012016:Reference Values; D013154:Spleen / Q000166:cytology / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology / Q000378:metabolism
chemical_list: D011388:Prolactin