Human fallopian tube as an extraovarian source of relaxin: messenger ribonucleic acid expression and cellular localization of immunoreactive protein and 125I-relaxin binding sites

Abstract

By means of specific human relaxin primers that originated from relaxin A and B chains, a monoclonal antibody, and 125I-relaxin, the expression of mRNA and immunoreactive protein and the presence of binding sites for relaxin were investigated in human fallopian tubes. Reverse transcription polymerase chain reaction (RT-PCR) analysis of total RNA isolated from tubal tissues revealed the predicted 434-bp fragments originating from both the H1 and H2 relaxin genes. Restriction enzyme digestion of the RT-PCR products with Msp I (Hpa II), present only in the relaxin H1 sequence, resulted in the anticipated 175- and 259-bp fragments, whereas digestion with Hpa I, which is present in the relaxin H2 sequence and should have resulted in 188- and 246-bp fragments, induced a limited and partial digestion of the product. Codigestion of the RT-PCR product with Msp I+Hpa I also resulted in 175- and 259-bp fragments. The immunoreactive relaxin protein was present primarily in the tubal epithelial cells of the ampullary and isthmus regions, and with weaker intensity in tubal smooth muscle cells. Immunoreactive relaxin either was barely present or was absent in other tubal cell types. The intensity of immunostaining for relaxin in the epithelial cells appeared not to be cycle-dependent; however, these cells showed a lower immunostaining at the late secretory phase of the menstrual cycle than at other reproductive stages and an absence of immunostaining during the postmenopausal period.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunohistochemical Detection of Relaxin Binding to the Volar Oblique Ligament

“…17 It also has been noted that relaxin production is not confined solely to the corpus luteum but has been attributed to the fallopian tubes. 18 The lack of histomorphometry renders comparisons between tissue sources qualitative. Additional work is needed to quantify areas of staining to allow more rigorous analysis.…”

International Union of Pharmacology LVII: Recommendations for the Nomenclature of Receptors for Relaxin Family Peptides

“…Relaxinbinding sites were identified in the uterus of rat (McMurtry et al, 1978;Cheah and Sherwood, 1980;Mercado-Simmen et al, 1980), mouse (McMurtry et al, 1978;Yang et al, 1992) and pig (Mercado et al, 1982); the pubic symphysis of mouse (McMurtry et al, 1978;Yang et al, 1992) and guinea pig (McMurtry et al, 1978); the cervix of pig (Mercado et al, 1982), rat (Weiss and Bryant, 1982) and guinea pig (McMurtry et al, 1978); the rat mammary gland (McMurtry et al, 1978); human fetal membranes (Koay et al, 1986); and fibroblasts from the mouse pubic symphysis and human skin (McMurtry et al, 1980). H2 relaxin contains a tyrosine residue that can be labeled by conventional chloramine-T iodination (Tang and Chegini, 1995). 125 I-H2 relaxin binds to epithelial, stromal, and smooth muscle cells in human fallopian tube, smooth muscle cells in the arterioles (Tang and Chegini, 1995), and fibroblasts isolated from human lower uterine segments (Palejwala et al, 1998).…”

“…H2 relaxin contains a tyrosine residue that can be labeled by conventional chloramine-T iodination (Tang and Chegini, 1995). 125 I-H2 relaxin binds to epithelial, stromal, and smooth muscle cells in human fallopian tube, smooth muscle cells in the arterioles (Tang and Chegini, 1995), and fibroblasts isolated from human lower uterine segments (Palejwala et al, 1998). 125 I-H2 relaxin labeled by an alternate strategy has also been used to characterize the binding activity of relaxin analogs (Bü llesbach and Schwabe, 2000).…”

Regulation of the reproductive cycle and early pregnancy by relaxin family peptides

“…The natural source of relaxin for such effects in vivo would either be from the ruptured follicle or the low circulating levels deriving from the new corpus luteum, though both sources would not be considerable. A further source is possibly from the oviduct itself (Tang and Chegini, 1995). The blastocyst is also expressing the relaxin-receptor, RXFP1, or shows specific relaxin-binding, in both trophoblast and inner cell mass (Einspanier et al, 2001;Vandevoort et al, 2011).…”