Biotinyl motilin as a biologically active receptor probe

Sakai, Takafumi; Satoh, Minoru; Hayashi, Hiroaki; Fujikura, Keiko; Sano, Isamu; Koyama, Haruko; Tatemoto, Kazuhiko

doi:10.1016/0196-9781(94)90011-6

Cited by 7 publications

(4 citation statements)

References 28 publications

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“…Second, in this study, specific relaxin binding was found in porcine theca and granulosa cells-two ovarian cell types in which porcine relaxin demonstrated a biological response in vitro [5,6]. Third, other investigators employed concentrations of biotinylated hormone probe similar to the concentration used in the present study to identify putative receptors for growth hormone and motilin in cultures of human lymphoid cells and rabbit gastric smooth muscle cells, respectively [25,26]. Accordingly, the remainder of this discussion is grounded on the premise that the relaxin-binding sites identified in the present study are, at least in part, relaxin receptors.…”

Section: Discussionmentioning

confidence: 85%

Localization of Specific Relaxin-Binding Cells in the Ovary and Testis of Pigs1

Min

Sherwood

1998

Biology of Reproduction

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It is not known whether relaxin has physiological roles in the gonads in mammalian species. Limited evidence indicates that relaxin may act locally to regulate ovarian function in pigs. The possibility of a role for relaxin in testicular function in pigs has not been investigated. A major initial step toward the establishment of direct effects of relaxin on the ovary and/or testis is to demonstrate that relaxin binds with specificity to the gonads. Accordingly, the first objective of this study was to employ an immunohistochemical localization technique to determine whether relaxin-binding cells are present in the ovaries and/or testis of pigs. Once they were found to be present, the second objective was to determine whether relaxin-binding sites noticeably change either within the ovary at different stages of the estrous cycle and pregnancy, or within the testis at sexual maturity. Ovaries were collected from four stages of the estrous cycle (midfollicular, late follicular, early luteal, and midluteal) and three stages of the pregnancy (Day 40, Day 80, and Day 110). Two gilts were used for each of the stages of the estrous cycle and pregnancy. Testes were collected from a 5-mo-old immature boar and a 36-mo-old mature boar. Tissues were cut into cubes (3-4 cm3), frozen in liquid nitrogen, and cryosectioned (8 microm). Specific cell types that bind relaxin were identified by sequential application of a biotinylated relaxin probe, antibiotin immunoglobulin G conjugated to 1 nm colloidal gold, and silver for signal amplification. In the ovary, specific relaxin-binding sites were localized in both the theca and granulosa cells of developing follicles, luteal cells, and blood vessels. In the testis, specific relaxin-binding sites were localized in the Leydig cells. There were no apparent differences in relaxin-binding distribution within the ovary at different stages of the estrous cycle and pregnancy in gilts, or within the testis at sexual maturity in boars. We conclude that the specific relaxin-binding cells within the ovary and testis of the pig may contain relaxin receptors. Therefore, relaxin may have effects in the ovary and testis of pigs.

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Section: Discussionmentioning

confidence: 85%

Localization of Specific Relaxin-Binding Cells in the Ovary and Testis of Pigs1

Min

Sherwood

1998

Biology of Reproduction

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“…Moreover, the area postrema is considered to be an important sensor in relaying information about glucose availability to the GnRH‐releasing system ( 10, 31). Another possibility is that peripheral motilin could be sensed by peripheral receptors distributed in the upper digestive tract to convey the information to the CNS through a peripheral neuronal pathway such as the vagus nerve, because the tract is abundant in motilin‐binding sites which is generally considered to play a role in the induction of gastric motility ( 32, 33). Motilin might also have a role as a neuromodulator as is known for other brain–gut peptides, i.e.…”

Section: Discussionmentioning

confidence: 99%

Peripheral or Central Administration of Motilin Suppresses LH Release in Female Rats: A Novel Role for Motilin

Tsukamura

Tsukahara

Maekawa

et al. 2000

J Neuroendocrinology

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Motilin is secreted in a clear episodic pattern during fasting or during the interdigestive phase, but feeding promptly stops this secretory pattern, and plasma concentrations of motilin decrease. We have previously determined that fasting markedly suppresses pulsatile luteinizing hormone (LH) secretion in female rats in the presence of oestrogen. In the present study, we wished to learn if motilin may mediate the fasting-induced suppression of LH secretion by determining the effects of motilin administration on LH release and on food intake. Intravenous (i.v.) injection of motilin (37 nmol/rat) suppressed LH release and significantly decreased mean LH concentrations both in ovariectomized (OVX) and oestradiol-implanted ovariectomized (OVX+E2) rats. Food intake was significantly increased by i.v. motilin injection in OVX rats, but not in OVX+E2 rats. It is likely that motilin inhibits LH release via inhibition of the gonadotrophin-releasing hormone (GnRH)-releasing mechanism at the hypothalamic level, because motilin (3.7 nmol/rat) also suppressed LH secretion when centrally administered, and because LH release in i.v. motilin-treated rats increased in response to exogenous GnRH. These results suggest that motilin may be a peripheral signal for the suppression of LH secretion through central sensors.

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“…The RC91T antiserum was diluted to a final concentration of 1:150,000. After incubation of the tubes for 24 h at 4°C, 10 l of [ 125 I](try 23 ) canine motilin (10,000 counts/min), which was prepared as previously described (21,32) was added to the tubes, followed by further incubation for 24 h at 4°C. The second antiserum (200 l) was added to the tubes and incubated at room temperature for 2 h. Bound and free [ 125 I]motilin were separated by centrifugation at 3,000 g for 15 min.…”

Section: Methodsmentioning

confidence: 99%

Interdigestive migrating contractions are coregulated by ghrelin and motilin in conscious dogs

Ogawa

Mochiki

Yanai

et al. 2012

American Journal of Physiology-Regulatory, Integrative and Comp

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During fasting, gastrointestinal (GI) motility is characterized by cyclical motor contractions. These contractions have been referred to as interdigestive migrating contractions (IMCs). In dogs and humans, IMCs are known to be regulated by motilin. However, in rats and mice, IMCs are regulated by ghrelin. It is not clear how these peptides influence each other in vivo. The aim of the present study was to investigate the relationship between ghrelin and motilin in conscious dogs. Twenty healthy beagles were used in this study. Force transducers were implanted in the stomach, duodenum, and jejunum to monitor GI motility. Subsequent GI motility was recorded and quantified by calculating the motility index. In examination 1, blood samples were collected in the interdigestive state, and levels of plasma ghrelin and motilin were measured. Plasma motilin peaks were observed during every gastric phase III, and plasma ghrelin peaks occurred in nearly every early phase I. Plasma motilin and ghrelin levels increased and decreased cyclically with the interdigestive states. In examination 2, saline or canine ghrelin was administered intravenously during phase II and phase III. After injection of ghrelin, plasma motilin levels were measured. Ghrelin injection during phases II and III inhibited phase III contractions and decreased plasma motilin levels. In examination 3, ghrelin was infused in the presence of the growth hormone secretagogue receptors antagonist [D-Lys3]-GHRP-6. Continuous ghrelin infusion suppressed motilin release, an effect abrogated by the infusion of [D-Lys3]-GHRP-6. Examination 4 was performed to evaluate the plasma ghrelin response to motilin administration. Motilin infusion immediately decreased ghrelin levels. In this study, we demonstrated that motilin and ghrelin cooperatively control the function of gastric IMCs in conscious dogs. Our findings suggest that ghrelin regulates the function and release of motilin and that motilin may also regulate ghrelin.

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Biotinyl motilin as a biologically active receptor probe

Cited by 7 publications

References 28 publications

Localization of Specific Relaxin-Binding Cells in the Ovary and Testis of Pigs1

Localization of Specific Relaxin-Binding Cells in the Ovary and Testis of Pigs1

Peripheral or Central Administration of Motilin Suppresses LH Release in Female Rats: A Novel Role for Motilin

Interdigestive migrating contractions are coregulated by ghrelin and motilin in conscious dogs

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