title: Stimulation of collagen secretion by relaxin and effect of oestrogen on relaxin binding in uterine cervical cells of pigs.
abstract: The role of relaxin and oestrogen in the remodelling of connective tissue was investigated by testing collagenase-dispersed cells (3 x 10(5) cells per well) from the uterine cervix of gilts for relaxin binding and collagen secretion. Relaxin-binding sites on these cells were quantified by specific binding of a saturating dose of 125I-labelled monotyrosyl relaxin at optimal conditions. Oestrogen at doses from 0.4 to 50 ng ml-1 increased relaxin binding in a time- and dose-dependent manner. Scatchard plot analysis exhibited curvilinearity, which suggested two classes of relaxin-binding sites. The addition of relaxin (0, 100, 500 ng ml-1) alone (P < 0.05) or in combination with oestrogen (oestradiol benzoate: 0, 50, 250 ng ml-1) increased protein secretion into the culture medium. Hydroxyproline concentration (as an index of collagen) in the medium was increased (P < 0.05) only in the presence of both relaxin and oestrogen. Actinomycin D (500 ng ml-1) and cycloheximide (500 ng ml-1) inhibited hydroxyproline secretion induced by combined relaxin and oestrogen treatment. Dibutyryl cyclic adenosine 3',5'-monophosphate (dibutyryl cAMP: 0, 0.1, 1.0, 5.0 mmol l-1) was a potent stimulator of hydroxyproline secretion. These results indicate that relaxin, probably via a cAMP pathway, stimulates hydroxyproline secretion in the presence of oestrogen through a protein- and RNA-synthesis dependent process. Oestrogen plays a role in augmenting the sensitivity of uterine cervical cells to relaxin in the pig.
authors.affiliation: Department of Animal Science, Iowa State University, Ames 50011-3150.
authors.forename: C
authors.initials: C
authors.lastname: Huang
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: L L
authors.initials: LL
authors.lastname: Anderson
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D002478:Cells, Cultured; D002584:Cervix Uteri / Q000187:drug effects / Q000378:metabolism*; D003094:Collagen / Q000096:biosynthesis*; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D012065:Relaxin / Q000378:metabolism / Q000494:pharmacology*; D013552:Swine
chemical_list: D004958:Estradiol; D012065:Relaxin; D003094:Collagen