Expression of Luteinizing Hormone Receptor in the Gastrointestinal Tract in Patients with and without Dysmotility

Leuprolide is a gonadotropin-releasing hormone (GnRH) analog which has been shown to reduce symptoms in patients with irritable bowel syndrome (IBS) and chronic intestinal pseudo-obstruction (CIPO). The mechanism is not known, but one hypothesis is through down-modulation of luteinizing hormone (LH) secretion, a hormone whith antagonistic effect on gastrointestinal motility. However, presence of LH receptors in the gastrointestinal tract has never been described. The aim of this study was to find one possible way of action for leuprolide by examining the presence of the LH receptor, and if present, to see whether there was different expression in patients with or without dysmotility. Full-thickness biopsies from the bowel wall of patients with and without severe dysmotility were examined using immunohistochemistry staining. Biopsies showed expression of LH receptors on myenteric neurons and in glial cells, neutrophils, endothelial cells and mast cells. There was no difference in expression between patient groups

Efecto de naxolona y morfina sobre el estradiol en la inducción de la curva de LH en ganado porcino

This study examines the role of endogenous opioids in control of the estradiol-induced luteinizing hormone (LH) surge. In the experiment 1 (Exp.1), fifteen Duroc gills were ovarieclomized at the age of 5 to 6 months and one month later challenged with estradiol benzoate (EB, 25 µg/kg i.m.) at 0 h of the experiment. Control animals (n=5) received continuos i.v. infusion of saline solution (5 ml/h) from 30 to 34 h and from 60 to 64 h preceded by single i.v- injection of 10 ml of saline in each case. The naloxone group (n=5) received naloxone (1 mg/ kg) continuously between 30 to 34 h after injection of EB, preceded by a single i.v. administration of the same amount of the drug. The morphine group (n=5) was given morphine (1 mg/kg) continuously from 60 to 64 h after EB preceded by a bolus i.v. injection of the same dose of opioid. In Exp.2 ten Duroc gills ovariectomized at the age of 6 months were prepared and challenged with EB in the same way as in Exp.1, The control group (n=5) received saline infusion from 54 to 60 h after the EB treatment while the naloxone group (n=5) received naloxone between 54 to 60 h. In Exp.1 EB alone suppressed LH values (pmol/l) from 28.1 - 36.9 to 2.2 - 4.4 during 6 to 48 h in all groups (negative feedback phase). In controls and NAL groups LH increased to 67.7±6.7 and 56.7±7.3 between 54 to 96 h (positive feedback phase), respectively (p>0.05). Hovewer, the beginning of LH surge was delayed for 6 h in naloxone given animals. LH in morphine treated gills was lower between 54 to 96 h than in controls and naloxone gills (p0,05). Sin embargo, el comienzo de la curva de LH fue retrasado por 6 horas en el grupo tratado con NAL. En las cerdas tratadas con morfina los valores de LH fueron más bajos entre las 54-96 h, comparados con el grupo control y las tratadas con NAL ( pa0,05). Estas datos muestran que mientras los péptidos-opioides endogenos pueden no estar involucrados en la acción inhibitoria del EB en la secreción de la LH, los opioides exógenos suprimen la curva de LH inducida por EB en cerdas

Effect of vaginal administration of prostaglandin E2 and/or 17Betta-estradiol on luteal function and histological characteristics of the cervix in cyclic pigs

The overall objective of this study was to examine the effect of vaginal administration of prostaglandin E₂ (PGE₂) and/or17β-estradiol (E₂) on luteal function maintenance and histological properties of the porcine cervix. For this purpose, crossbred gilts were divided into three groups (n=5 per group) supplied on days 11-16 of the estrous cycle with suppositories containing: (1) placebo (Group I, Control); (2) 0.4 mg of E₂ (Group II); (3) 0.4 mg of E₂ and 2 mg of PGE₂ (Group III). Blood samples were collected on days 11-19 of the estrous cycle to determine the concentration of progesterone (P₄). Additionally, to examine local effects of the hormones applied, segments from the uterine and vaginal parts of the cervix and from the ovaries were collected post-mortem. Prolonged luteal function and extended synthesis of P₄ were observed in 2 of 5 gilts receiving PGE₂ and E₂ simultaneously (Group III). Then, these gilts were subdivided into Group IIIA (n=2; presence of corpora lutea on the ovaries) and Group IIIB (n=3; lack of corpora lutea). Increased levels of plasma P₄ were observed in Group IIIA on days 15-19 compared to Group IIIB and on days 16-19 compared to Group I and Group II (P<0.05; P<0.01; P<0.001, respectively). In the cervix of gilts in Groups II and III, enlarged blood vessels in the lamina propria of both parts of the cervix were observed. Furthermore, in Group II the epithelium of the uterine part of the cervix was thicker (P<0.001). Our study confirmed the proposed luteotrophic/antiluteolytic actions of E₂ and PGE₂ applied intravaginally. These results are significant considering that very low doses of E₂ were used when compared to previous attempts. Despite the inadequate response to treatments in some of the gilts, the local effects of these hormones on the histological properties of the porcine cervix suggest that further improvements in the vaginal administration route might help to elaborate new methods for enhancing the luteal function in the pig

The novel effect of hCG administration on luteal function maintenance during the estrous cycle/pregnancy and early embryo development in the pig

Two independent experiments were performed on cyclic (Experiment I) and pregnant (Experiment II) gilts to examine the effect of human Chorionic Gonadotropin (hCG) administration on day 12 of the estrous cycle/pregnancy on ovarian and endometrial secretory function. Animals were divided into hCG Group (injection of 750 IU hCG) and Control Group (injection of saline). In Experiment I, the prolonged lifespan of the corpus luteum (CL), extended progesterone (P4) production (P<0.05) and delayed luteolysis were found. In hCG Group increased ratio of PGE2:PGFM during 12 hrs period on day 15 (P<0.05) of the estrous cycle was observed. In both experiments, higher concentrations of E2 in hCG treated gilts (P<0.05) on days 14-15 of the estrous cycle/pregnancy were found. In Experiment II, hCG injection did not affect P4, PGE2 and PGFM concentrations in blood plasma, but reduced the number of resorbed embryos on day 30 of pregnancy. In the pregnant hCG treated gilts the immunostaining against von Willebrand Factor (vWF) demonstrated an enhanced (P<0.05) angiogenesis in CLs and endometrium. Furthermore, the flow cytometry revealed an increased (P<0.05) viability of cells in CLs of hCG Group. An augmented expression of Steroidogenic Acute Regulatory Protein (STAR; P<0.05) and LH/hCG receptor mRNA (P<0.05) in CLs of hCG Group were observed, but an elevated concentration of protein was confirmed only for STAR (P<0.05). Our studies revealed, for the first time, that administration of hCG affects PGE2:PGFM ratio during the estrous cycle as well as the development of conceptuses through enhanced angiogenesis and decreased luteal apoptosis in early pregnant pigs