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1.
N Z Med J ; 129(1434): 49-58, 2016 May 06.
Article in English | MEDLINE | ID: mdl-27349263

ABSTRACT

AIMS: In light of the rising number of referrals to secondary level services of people who identify as transgender, and the Human Rights Commission concerns regarding the care of this group in New Zealand, we felt it was timely to determine the availability of services for people who identify as transgender and whether there are variations in management protocols. METHODS: We contacted 100 physicians involved in providing a secondary level service to care for people who identify as transgender, and asked them to complete a questionnaire about the services available in their region. This questionnaire consisted of two parts, a 'general questionnaire', which focussed on the consultants' understanding of services available locally, and a 'clinical questionnaire', which presented hypothetical clinical case histories and asked respondents to indicate how they would manage the case. RESULTS: Sixty-two of the physicians responded. Of these, 18 (45% of the 40 physicians that answered the question) believed they could access a psychological or psychiatric opinion in the public sector for a patient who identifies as transgender, whereas 28 (82% of the 34 that answered the question) knew of access in the private sector. There was a conflict of opinion on the availability of psychological and surgical services in several DHBs where there was more than one clinician responding. This may reflect the case experience of individual clinicians. There was restricted access to common surgical procedures in the public sector, and about half of respondents did not know if techniques were available locally. CONCLUSIONS: Our results support the development of specialist care services in tertiary centres in addition to the secondary services already available in New Zealand for people who identify as transgender. Development of multidisciplinary management and improved access to psychological support services for individual cases is required.


Subject(s)
Attitude of Health Personnel , Health Services Accessibility/statistics & numerical data , Physician-Patient Relations , Primary Health Care/methods , Transgender Persons , Disease Management , Female , Health Care Surveys , Humans , Male , New Zealand
2.
Pak J Med Sci ; 31(5): 1250-5, 2015.
Article in English | MEDLINE | ID: mdl-26649024

ABSTRACT

UNLABELLED: Fasting during the month of Ramadan is a religious rituals of all healthy adult Muslims. However, there is no clear agreement on the effects of Ramadan fasting on cardiovascular disease. Comorbidities and factors such as age, gender, health status, daily duration of fasting, food intake before and after fasting may impact on a fasting individual's cardiometabolic risk. This review was undertaken to assess the effects of Ramadan fasting on: the incidence of cardiovascular disease during the month of Ramadan; the clinical status of patients with stable cardiac disease; and any alterations in cardiometabolic risk profile. METHODS: A systematic search was undertaken for studies that investigated the impact of Ramadan fasting on cardiovascular outcomes and risk factors. Electronic databases including MEDLINE, Scopus and Web of Knowledge were searched from 1982 up to 2014. The incidence of acute cardiac illness during Ramadan fasting was similar when compared to non-fasting days. Ramadan fasting is associated with elevations in high-density lipoprotein cholesterol (HDL-c), and reductions in low-density lipoprotein cholesterol (LDL-c) and total cholesterol (T-chol). However, the lipid profile of diabetic patients deteriorated significantly during Ramadan fasting. In addition, Ramadan fasting lowers body weight, body fat percentage and BMI (body mass index). However, the relationship between weight reduction and loss of body fat is not studied. The majority of patients with stable cardiac illness can opt for Ramadan fasting safely. However, the long term effects of Ramadan fasting on cardiovascular outcomes and risk factors remains uncertain, and the apparent discordant effects in individuals with and without diabetes mellitus merits further study.

3.
Br J Clin Pharmacol ; 70(5): 674-81, 2010 Nov.
Article in English | MEDLINE | ID: mdl-21039761

ABSTRACT

AIMS: To investigate (i) if kisspeptin administration alters heart rate (HR) or blood pressure (BP) in healthy male and female volunteers, (ii) whether circulating plasma kisspeptin concentrations in healthy pregnant women and women with hypertensive diseases of pregnancy correlate with BP and (iii) whether women with hypertensive diseases of pregnancy have altered plasma kisspeptin concentrations. METHODS: We have previously reported the effects of administration of kisspeptin-54 on gonadotrophin secretion in healthy male and female volunteers. In these studies, cardiovascular parameters were not a primary endpoint. However, data were also collected on BP and HR for 4h post administration of kisspeptin-54. Blood samples were taken from 105 women in the third trimester of pregnancy (27 women with hypertensive diseases of pregnancy and 78 controls). Samples were assayed for plasma kisspeptin immunoreactivity (IR). RESULTS: Administration of kisspeptin was not associated with significant changes in HR or BP in healthy men or women. There was no significant correlation between plasma kisspeptin concentration and BP in healthy pregnant women or in those with hypertensive diseases of pregnancy. No significant differences in plasma kisspeptin-IR concentrations were observed between women with hypertensive diseases of pregnancy and normotensive pregnant controls, plasma kisspeptin concentrations ±SE: controls 2878 ± 157pmol l(-1) ; pregnancy-induced hypertension 2696 ± 299pmoll(-1) (95% CI vs. controls -514, 878pmoll(-1) ); pre-eclampsia 3519 ± 357 (95% CI vs. controls -1644, 362pmoll(-1) ). CONCLUSIONS: Elevation of plasma kisspeptin-IR is not associated with an alteration in BP in humans.


Subject(s)
Blood Pressure/drug effects , Blood Pressure/physiology , Hypertension, Pregnancy-Induced/physiopathology , Pre-Eclampsia/physiopathology , Pregnancy Complications, Cardiovascular/physiopathology , Tumor Suppressor Proteins/blood , Tumor Suppressor Proteins/pharmacology , Adult , Case-Control Studies , Female , Heart Rate/drug effects , Heart Rate/physiology , Humans , Hypertension, Pregnancy-Induced/blood , Kisspeptins , Male , Pre-Eclampsia/blood , Pregnancy , Pregnancy Complications, Cardiovascular/blood , Pregnancy Trimester, Third
4.
Nat Rev Endocrinol ; 6(8): 444-53, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20585346

ABSTRACT

Food intake and energy expenditure are tightly regulated by the brain, in a homeostatic process that integrates diverse hormonal, neuronal and metabolic signals. The gastrointestinal tract is an important source of such signals, which include several hormones released by specialized enteroendocrine cells. These hormones exert powerful effects on appetite and energy expenditure. This Review addresses the physiological roles of peptide YY, pancreatic polypeptide, islet amyloid polypeptide, glucagon-like peptide 1, glucagon, oxyntomodulin, cholecystokinin and ghrelin and discusses their potential as targets for the development of novel treatments for obesity.


Subject(s)
Brain/metabolism , Gastrointestinal Hormones/metabolism , Obesity/metabolism , Humans , Models, Biological
5.
Oncol Rep ; 23(6): 1729-34, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20428832

ABSTRACT

Kisspeptin, the product of the KiSS-1 gene, inhibits metastasis and stimulates the hypothalamo-pituitary-gonadal axis. Kisspeptin is therefore a putative target in the treatment of hormone-sensitive malignancies. Prostatic carcinoma remains a significant cause of mortality despite improvements in therapy. The role of kisspeptin in prostatic carcinoma remains undefined. We therefore aimed to investigate release of kisspeptin by prostatic cancer cell lines; investigate expression of KiSS-1 in human prostate tissue; investigate whether patients with prostate carcinoma have elevated plasma kisspeptin. 1) Culture medium from prostatic carcinoma cell lines LNCaP, DU145 and PC3 was assayed for kisspeptin immunoreactivity (-IR). Kisspeptin-IR release was detectable from all three cell lines. The effect of hydroxyflutamide, gefitinib and resveratrol on kisspeptin-IR release from these cell lines was also investigated. No effect of the drugs tested on release of kisspeptin-IR was observed. 2) Expression of KiSS-1 in human prostate tissue (n=4) was investigated using in situ hybridisation. Expression of KiSS-1 was detected in human prostate tissue. 3) Plasma kisspeptin-IR was compared in 92 patients with prostatic carcinoma and 73 male controls. Kisspeptin-IR was not detected in the plasma of either patients with prostate cancer or control patients. We have therefore shown for the first time the release of kisspeptin-IR by prostatic carcinoma cell lines. We have also shown that KiSS-1 is expressed in human prostate tissue, and that circulating levels of kisspeptin-IR are not elevated in patients with prostatic carcinoma. Further work is required to determine the role of kisspeptin in the prostate.


Subject(s)
Prostatic Neoplasms/metabolism , Tumor Suppressor Proteins/blood , Tumor Suppressor Proteins/metabolism , Aged , Humans , In Situ Hybridization , Kisspeptins , Male , Prostatic Neoplasms/genetics , RNA, Antisense/pharmacology , Tumor Cells, Cultured , Tumor Suppressor Proteins/genetics
7.
Br J Clin Pharmacol ; 68(6): 830-43, 2009 Dec.
Article in English | MEDLINE | ID: mdl-20002077

ABSTRACT

Our knowledge of the complex mechanisms underlying energy homeostasis has expanded enormously in recent years. Food intake and body weight are tightly regulated by the hypothalamus, brainstem and reward circuits, on the basis both of cognitive inputs and of diverse humoral and neuronal signals of nutritional status. Several gut hormones, including cholecystokinin, glucagon-like peptide-1, peptide YY, oxyntomodulin, amylin, pancreatic polypeptide and ghrelin, have been shown to play an important role in regulating short-term food intake. These hormones therefore represent potential targets in the development of novel anti-obesity drugs. This review focuses on the role of gut hormones in short- and long-term regulation of food intake, and on the current state of development of gut hormone-based obesity therapies.


Subject(s)
Anti-Obesity Agents/therapeutic use , Appetite Depressants/therapeutic use , Appetite Regulation/drug effects , Gastrointestinal Agents/therapeutic use , Obesity/drug therapy , Amyloid/therapeutic use , Cholecystokinin/therapeutic use , Eating/physiology , Energy Metabolism/physiology , Ghrelin/therapeutic use , Humans , Islet Amyloid Polypeptide , Oxyntomodulin/therapeutic use , Pancreatic Polypeptide/therapeutic use , Peptide YY/therapeutic use
8.
J Clin Endocrinol Metab ; 94(11): 4315-23, 2009 Nov.
Article in English | MEDLINE | ID: mdl-19820030

ABSTRACT

BACKGROUND: Kisspeptin is a critical regulator of normal reproductive function. A single injection of kisspeptin in healthy human volunteers potently stimulates gonadotropin release. However, the effects of kisspeptin on gonadotropin release in women with hypothalamic amenorrhea (HA) and the effects of repeated administration of kisspeptin to humans are unknown. AIM: The aim of this study was to determine the effects of acute and chronic kisspeptin administration on gonadotropin release in women with HA. METHODS: We performed a prospective, randomized, double-blinded, parallel design study. Women with HA received twice-daily sc injections of kisspeptin (6.4 nmol/kg) or 0.9% saline (n = 5 per group) for 2 wk. Changes in serum gonadotropin and estradiol levels, LH pulsatility, and ultrasound measurements of reproductive activity were assessed. RESULTS: On the first injection day, potent increases in serum LH and FSH were observed after sc kisspeptin injection in women with HA (mean maximal increment from baseline within 4 h after injection: LH, 24.0 +/- 3.5 IU/liter; FSH, 9.1 +/- 2.5 IU/liter). These responses were significantly reduced on the 14th injection day (mean maximal increment from baseline within 4 h postinjection: LH, 2.5 +/- 2.2 IU/liter, P < 0.05; FSH, 0.5 +/- 0.5 IU/liter, P < 0.05). Subjects remained responsive to GnRH after kisspeptin treatment. No significant changes in LH pulsatility or ultrasound measurements of reproductive activity were observed. CONCLUSION: Acute administration of kisspeptin to women with infertility due to HA potently stimulates gonadotropin release, but chronic administration of kisspeptin results in desensitization to its effects on gonadotropin release. These data have important implications for the development of kisspeptin as a novel therapy for reproductive disorders in humans.


Subject(s)
Amenorrhea/drug therapy , Gonadotropins/metabolism , Tachyphylaxis/physiology , Tumor Suppressor Proteins/therapeutic use , Adult , Body Mass Index , Body Weight , Female , Follicle Stimulating Hormone/blood , Gonadotropins/blood , Humans , Hypothalamus/physiopathology , Kisspeptins , Luteinizing Hormone/blood , Spectrometry, Mass, Electrospray Ionization/methods , Tumor Suppressor Proteins/adverse effects , Tumor Suppressor Proteins/chemistry , Weight Gain , Young Adult
9.
Neuroimage ; 44(3): 1022-31, 2009 Feb 01.
Article in English | MEDLINE | ID: mdl-18983926

ABSTRACT

We have used manganese-enhanced magnetic resonance imaging (MEMRI) to show distinct patterns of neuronal activation within the hypothalamus and brainstem of fasted mice in response to peripheral injection of the anorexigenic agents glucagon-like peptide-1 (GLP-1), oxyntomodulin (OXM) and lithium chloride. Administration of both GLP-1 and OXM resulted in a significant increase in signal intensity (SI) in the area postrema of fasted mice, reflecting an increase in neuronal activity within the brainstem. In the hypothalamus, GLP-1 administration induced a significant reduction in SI in the paraventricular nucleus and an increase in the ventromedial hypothalamic nucleus whereas OXM reduced SI in the arcuate and supraoptic nuclei of the hypothalamus. These data indicate that whilst these related peptides both induce a similar effect on neuronal activity in the brainstem they generate distinct patterns of activation within the hypothalamus. Furthermore, the hypothalamic pattern of signal intensity generated by GLP-1 closely matches that generated by peripheral injection of LiCl, suggesting the anorexigenic effects of GLP-1 may be in part transmitted via nausea circuits. This work provides a framework by which the temporal effects of appetite modulating agents can be recorded simultaneously within hypothalamic and brainstem feeding centres.


Subject(s)
Brain Stem/physiology , Chlorides , Glucagon-Like Peptide 1/administration & dosage , Hypothalamus/physiology , Lithium Chloride/administration & dosage , Magnetic Resonance Imaging/methods , Manganese Compounds , Neurons/physiology , Oxyntomodulin/administration & dosage , Animals , Appetite Stimulants/administration & dosage , Brain Mapping/methods , Brain Stem/drug effects , Contrast Media , Hypothalamus/drug effects , Image Enhancement/methods , Injections , Male , Mice , Mice, Inbred C57BL , Nerve Net/drug effects , Nerve Net/physiology
10.
Obesity (Silver Spring) ; 17(2): 396-401, 2009 Feb.
Article in English | MEDLINE | ID: mdl-19057524

ABSTRACT

Evidence suggests that a low-glycemic index (LGI) diet has a satiating effect and thus may enhance weight maintenance following weight loss. This study was conducted at Hammersmith Hospital, London, UK, and assessed the effect of altering diet GI on weight-loss maintenance. It consisted of a weight-loss phase and a 4-month randomized weight maintenance phase. Subjects were seen monthly to assess dietary compliance and anthropometrics. Appetite was assessed bimonthly by visual analogue scales while meal challenge postprandial insulin and glucose concentrations were assessed before and after the intervention. Following a median weight loss of 6.1 (interquartile range: 5.2-7.1) % body weight, subjects were randomized to a high-glycemic index (HGI) (n = 19) or LGI (n = 23) diet. Dietary composition differed only in GI (HGI group: 63.7 +/- 9.4; LGI group: 49.7 +/- 5.7, P < 0.001) and glycemic load (HGI group: 136.8 +/- 56.3; LGI group: 89.7 +/- 27.5, P < 0.001). Groups did not differ in body weight (weight change over 4 months, HGI group: 0.3 +/- 1.9 kg; LGI group: -0.7 +/- 2.9 kg, P = 0.3) or other anthropometric measurements. This pilot study suggests that in the setting of healthy eating, changing the diet GI does not appear to significantly affect weight maintenance.


Subject(s)
Diet , Glycemic Index , Obesity/physiopathology , Overweight/physiopathology , Weight Loss/physiology , Adolescent , Adult , Aged , Appetite/physiology , Body Weight/physiology , Eating/physiology , Humans , Middle Aged , Pain Measurement , Pilot Projects , Young Adult
11.
Neuroendocrinology ; 89(2): 121-30, 2009.
Article in English | MEDLINE | ID: mdl-18849597

ABSTRACT

The global increase in obesity has led to a redoubling of efforts directed at understanding the control of energy homeostasis. Insight into the mechanisms which govern appetite regulation is central to understanding the pathophysiology of obesity and the design of effective therapeutic interventions. Exploitation of hormonal satiety signals secreted by the gut requires greater insight into their interaction with central nervous system (CNS) circuits of appetite control. Manganese-enhanced magnetic resonance imaging is a novel technique, recently adapted to investigate the effects of gut peptides on CNS appetite circuits. Using manganese ion accumulation as a marker of neuronal activity, changes in signal intensity in key appetite centres within the hypothalamus following peripheral injection of gut hormones have been demonstrated. Manganese-enhanced magnetic resonance imaging offers several advantages over methodologies currently used for the study of gut hormone interactions with the CNS and has the potential for application in fields beyond appetite regulation.


Subject(s)
Appetite Regulation/physiology , Central Nervous System/metabolism , Central Nervous System/physiology , Magnetic Resonance Imaging/methods , Manganese/metabolism , Neural Pathways/metabolism , Neural Pathways/physiology , Animals , Blood-Brain Barrier , Brain Mapping/methods , Gastrointestinal Hormones/metabolism , Gastrointestinal Hormones/physiology , Humans , Image Enhancement/methods , Manganese/administration & dosage , Time Factors
12.
Diabetes Care ; 31 Suppl 2: S284-9, 2008 Feb.
Article in English | MEDLINE | ID: mdl-18227498

ABSTRACT

The current obesity epidemic is fuelled by the availability of highly palatable, calorie-dense food, and the low requirement for physical activity in our modern environment. If energy intake exceeds energy use, the excess calories are stored as body fat. Although the body has mechanisms that act to maintain body weight over time, they primarily defend against starvation and are less robust in preventing the development of obesity. Knowledge of this homeostatic system that controls body weight has increased exponentially over the last decade and has revealed new possibilities for the treatment of obesity and its associated comorbidities. One therapeutic target is the development of agents based on the gastrointestinal hormones that control appetite. This review discusses the hormones oxyntomodulin, peptide YY, glucagon-like peptide 1, pancreatic polypeptide, and ghrelin and their emerging potential as anti-obesity treatments.


Subject(s)
Appetite Depressants/therapeutic use , Gastrointestinal Hormones/therapeutic use , Obesity/prevention & control , Brain/physiology , Brain/physiopathology , Diet , Energy Intake , Gastrointestinal Tract/physiology , Gastrointestinal Tract/physiopathology , Ghrelin/therapeutic use , Glucagon-Like Peptide 1/therapeutic use , Humans , Neurons/physiology , Obesity/epidemiology
13.
Am J Physiol Endocrinol Metab ; 294(4): E698-708, 2008 Apr.
Article in English | MEDLINE | ID: mdl-18285527

ABSTRACT

Peptide YY (PYY) is secreted postprandially from the endocrine L cells of the gastrointestinal tract. PYY(3-36), the major circulating form of the peptide, is thought to reduce food intake in humans and rodents via high-affinity binding to the autoinhibitory neuropeptide Y (NPY) receptor within the arcuate nucleus. We studied the effect of early light-phase injection of PYY(3-36) on food intake in mice fasted for 0, 6, 12, 18, 24, and 30 h and show that PYY(3-36) produces an acute anorexigenic effect regardless of the duration of fasting. We also show evidence of a delayed orexigenic effect in ad libitum-fed mice injected with PYY(3-36) in the early light phase. This delayed orexigenic effect also occurs in mice administered a potent analog of PYY(3-36), d-Allo Ile(3) PYY(3-36), but not following injection of other anorectic agents (glucagon-like-peptide 1, oxyntomodulin, and lithium chloride). Early light-phase injection of PYY(3-36) to ad libitum-fed mice resulted in a trend toward increased levels of hypothalamic NPY and agouti-related peptide mRNA and a decrease in proopiomelanocortin mRNA at the beginning of the dark phase. Furthermore, plasma levels of ghrelin were increased significantly, and there was a trend toward decreased plasma PYY(3-36) levels at the beginning of the dark phase. These data indicate that PYY(3-36) injection results in an acute anorexigenic effect followed by a delayed orexigenic effect.


Subject(s)
Appetite Depressants/pharmacology , Eating/drug effects , Intracellular Signaling Peptides and Proteins/metabolism , Neuropeptides/metabolism , Peptide YY/pharmacology , Satiety Response/drug effects , Agouti-Related Protein/genetics , Agouti-Related Protein/metabolism , Animals , Antimanic Agents/pharmacology , Dose-Response Relationship, Drug , Fasting , Glucagon-Like Peptide 1/pharmacology , Hypothalamus/drug effects , Hypothalamus/physiology , Incretins/pharmacology , Injections, Intraperitoneal , Lithium Chloride/pharmacology , Male , Mice , Mice, Inbred C57BL , Neuropeptide Y/genetics , Neuropeptide Y/metabolism , Orexins , Oxyntomodulin/pharmacology , Peptide Fragments , Pro-Opiomelanocortin/genetics , Pro-Opiomelanocortin/metabolism , RNA, Messenger/metabolism , Specific Pathogen-Free Organisms
14.
Annu Rev Physiol ; 70: 239-55, 2008.
Article in English | MEDLINE | ID: mdl-17937600

ABSTRACT

The increasing prevalence of obesity worldwide has imparted renewed impetus to the study of the mechanisms of appetite regulation. Digestion and nutrient absorption take place in the gastrointestinal (GI) tract, whereas food intake is controlled by neuronal circuits in the central nervous system. The need for gut-brain cross talk is therefore clear. It is now recognized that hormones released into the circulation from the GI tract in response to nutritional stimuli form a key component of this gut-brain axis. Peptides such as glucagon-like peptide-1, oxyntomodulin, pancreatic polypeptide, and peptide YY3-36 reduce food intake in both animal models and in humans. Physiologically, such peptides are thought to act as satiety signals and meal terminators. Here, we review the current state of the field of the effects of gut hormone action on appetite control.


Subject(s)
Enteric Nervous System/physiology , Gastrointestinal Hormones/metabolism , Gastrointestinal Tract/physiology , Satiety Response/physiology , Signal Transduction/physiology , Animals , Gastrointestinal Tract/innervation , Humans , Vagus Nerve/physiology
15.
J Neurosci ; 27(45): 12341-8, 2007 Nov 07.
Article in English | MEDLINE | ID: mdl-17989298

ABSTRACT

Hormonal satiety signals secreted by the gut play a pivotal role in the physiological control of appetite. However, therapeutic exploitation of the gut-brain axis requires greater insight into the interaction of gut hormones with CNS circuits of appetite control. Using the manganese ion (Mn2+) as an activity-dependent magnetic resonance imaging (MRI) contrast agent, we showed an increase in signal intensity (SI) in key appetite-regulatory regions of the hypothalamus, including the arcuate, paraventricular, and ventromedial nuclei, after peripheral injection of the orexigenic peptide ghrelin. Conversely, administration of the anorexigenic hormone peptide YY(3-36) caused a reduction in SI. In both cases, the changes in SI recorded in the hypothalamic arcuate nucleus preceded the effect of these peptides on food intake. Intravenous Mn2+ itself did not significantly alter ghrelin-mediated expression of the immediate early gene product c-Fos, nor did it cause abnormalities of behavior or metabolic parameters. We conclude that manganese-enhanced MRI constitutes a powerful tool for the future investigation of the effects of drugs, hormones, and environmental influences on neuronal activity.


Subject(s)
Central Nervous System/metabolism , Gastrointestinal Hormones/metabolism , Magnetic Resonance Imaging , Neuropeptide Y/metabolism , Animals , Brain/metabolism , Brain/physiology , Central Nervous System/physiology , Eating/physiology , Ghrelin/metabolism , Ghrelin/physiology , Magnetic Resonance Imaging/methods , Male , Mice , Mice, Inbred C57BL , Neuropeptide Y/administration & dosage , Neuropeptide Y/physiology , Time Factors
16.
J Clin Endocrinol Metab ; 92(10): 3958-66, 2007 Oct.
Article in English | MEDLINE | ID: mdl-17635940

ABSTRACT

CONTEXT: Kisspeptin, the endogenous ligand of the G protein-coupled receptor 54, is a key regulator of the hypothalamo-pituitary-gonadal (HPG) axis. GPR54-null mice exhibit reproductive dysfunction, and exogenous kisspeptin potently stimulates the HPG axis in rodents, primates, and human males. The effects of kisspeptin administration to human females are unknown. OBJECTIVE: Our objective was to investigate the effects of kisspeptin on LH release during the menstrual cycle in female volunteers. DESIGN: Bolus sc kisspeptin-54 was administered to female volunteers, and plasma gonadotropins were measured. SETTING: The study took place at a hospital clinical research facility. VOLUNTEERS: Subjects were healthy female volunteers with regular menstrual cycles. INTERVENTION: 1) Volunteers received a sc bolus injection of kisspeptin-54 (0, 0.2, 0.4, 0.8, 1.6, 3.2, and 6.4 nmol/kg; n = 3-4 per dose) in the follicular phase; and 2) volunteers (n = 8) received a sc bolus injection of either kisspeptin-54 (0.4 nmol/kg) or saline in random order during each phase of the menstrual cycle. MAIN OUTCOME MEASURES: Plasma gonadotropins were measured. RESULTS: 1) Kisspeptin-54 caused a dose-dependent increase in mean LH over time at doses from 0.2-6.4 nmol/kg. 2) Kisspeptin-54 increased plasma LH compared with saline injection in all phases of the cycle. The effect of kisspeptin was greatest in the preovulatory phase and least in the follicular phase of the cycle [mean increase in LH over baseline (IU/liter) +/- sem for follicular phase was 0.12 +/- 0.17; preovulatory phase, 20.64 +/- 2.91 (P < 0.001 vs. follicular phase); luteal phase, 2.17 +/- 0.79 (P < 0.01 vs. follicular phase)]. CONCLUSION: Elevation of plasma kisspeptin in human females potently stimulates LH release in the preovulatory phase and provides a novel mechanism for manipulation of the HPG axis in women.


Subject(s)
Follicular Phase/drug effects , Hypothalamo-Hypophyseal System/drug effects , Luteinizing Hormone/blood , Tumor Suppressor Proteins/administration & dosage , Adult , Amenorrhea/drug therapy , Amenorrhea/metabolism , Dose-Response Relationship, Drug , Female , Follicle Stimulating Hormone/blood , Follicular Phase/metabolism , Humans , Hypothalamo-Hypophyseal System/metabolism , Injections, Subcutaneous , Kisspeptins , Luteinizing Hormone/metabolism , Tumor Suppressor Proteins/metabolism
17.
Biochem Biophys Res Commun ; 350(2): 298-306, 2006 Nov 17.
Article in English | MEDLINE | ID: mdl-17007819

ABSTRACT

The anorexigenic gut hormones oxyntomodulin (OXM) and glucagon-like peptide-1 (GLP-1) are thought to physiologically regulate appetite and food intake. Using manganese-enhanced magnetic resonance imaging, we have shown distinct patterns of neuronal activation in the hypothalamus in response to intraperitoneal injections into fasted mice of 900 and 5400 nmol/kg OXM or 900 nmol/kg GLP-1. Administration of OXM at either dose resulted in a reduced rate of signal enhancement, reflecting a reduction in neuronal activity, in the arcuate, paraventricular, and supraoptic nuclei of the hypothalamus. Conversely, GLP-1 caused a reduction in signal enhancement in the paraventricular nucleus only and an increase in the ventromedial hypothalamic nucleus. Our data show that these two apparently similar peptides generate distinct patterns of activation within the hypothalamus, suggesting that GLP-1 and OXM may act via different hypothalamic pathways.


Subject(s)
Eating , Glucagon-Like Peptide 1/pharmacology , Hypothalamus/physiology , Neurons/physiology , Oxyntomodulin/pharmacology , Peptide Fragments/pharmacology , Animals , Eating/drug effects , Fasting , Glucagon-Like Peptide 1/administration & dosage , Hypothalamus/anatomy & histology , Hypothalamus/cytology , Injections , Injections, Intraperitoneal , Kinetics , Magnetic Resonance Imaging/methods , Male , Manganese/analysis , Mice , Mice, Inbred C57BL , Neurons/drug effects , Oxyntomodulin/administration & dosage , Peptide Fragments/administration & dosage
18.
Philos Trans R Soc Lond B Biol Sci ; 361(1471): 1187-209, 2006 Jul 29.
Article in English | MEDLINE | ID: mdl-16815798

ABSTRACT

The role of gastrointestinal hormones in the regulation of appetite is reviewed. The gastrointestinal tract is the largest endocrine organ in the body. Gut hormones function to optimize the process of digestion and absorption of nutrients by the gut. In this capacity, their local effects on gastrointestinal motility and secretion have been well characterized. By altering the rate at which nutrients are delivered to compartments of the alimentary canal, the control of food intake arguably constitutes another point at which intervention may promote efficient digestion and nutrient uptake. In recent decades, gut hormones have come to occupy a central place in the complex neuroendocrine interactions that underlie the regulation of energy balance. Many gut peptides have been shown to influence energy intake. The most well studied in this regard are cholecystokinin (CCK), pancreatic polypeptide, peptide YY, glucagon-like peptide-1 (GLP-1), oxyntomodulin and ghrelin. With the exception of ghrelin, these hormones act to increase satiety and decrease food intake. The mechanisms by which gut hormones modify feeding are the subject of ongoing investigation. Local effects such as the inhibition of gastric emptying might contribute to the decrease in energy intake. Activation of mechanoreceptors as a result of gastric distension may inhibit further food intake via neural reflex arcs. Circulating gut hormones have also been shown to act directly on neurons in hypothalamic and brainstem centres of appetite control. The median eminence and area postrema are characterized by a deficiency of the blood-brain barrier. Some investigators argue that this renders neighbouring structures, such as the arcuate nucleus of the hypothalamus and the nucleus of the tractus solitarius in the brainstem, susceptible to influence by circulating factors. Extensive reciprocal connections exist between these areas and the hypothalamic paraventricular nucleus and other energy-regulating centres of the central nervous system. In this way, hormonal signals from the gut may be translated into the subjective sensation of satiety. Moreover, the importance of the brain-gut axis in the control of food intake is reflected in the dual role exhibited by many gut peptides as both hormones and neurotransmitters. Peptides such as CCK and GLP-1 are expressed in neurons projecting both into and out of areas of the central nervous system critical to energy balance. The global increase in the incidence of obesity and the associated burden of morbidity has imparted greater urgency to understanding the processes of appetite control. Appetite regulation offers an integrated model of a brain-gut axis comprising both endocrine and neurological systems. As physiological mediators of satiety, gut hormones offer an attractive therapeutic target in the treatment of obesity.


Subject(s)
Appetite Regulation/physiology , Gastrointestinal Hormones/physiology , Gastrointestinal Tract/physiology , Humans
19.
Am J Physiol Endocrinol Metab ; 291(5): E878-84, 2006 Nov.
Article in English | MEDLINE | ID: mdl-16757546

ABSTRACT

Kisspeptin is a 54-amino acid peptide, encoded by the anti-metastasis gene KiSS-1, that activates G protein-coupled receptor 54 (GPR54). The kisspeptin-GPR54 system is critical to normal reproductive development. KiSS-1 gene expression is increased in the human placenta in normal and molar pregnancies. Circulating kisspeptin is dramatically increased in normal pregnancy, but levels in GTN have not previously been reported. The present study was designed to determine whether plasma kisspeptin levels are altered in patients with malignant GTN. Thirty-nine blood samples were taken from 11 patients with malignant GTN at presentation during and after chemotherapy. Blood was also sampled from nonpregnant and pregnant volunteers. Plasma kisspeptin IR and hCG concentrations were measured. Plasma kisspeptin IR concentration in nonpregnant (n = 16) females was <2 pmol/l. Plasma kisspeptin IR in females was 803 +/- 125 pmol/l in the first trimester of pregnancy (n = 13), 2,483 +/- 302 pmol/l in the third trimester of pregnancy (n = 7), and <2 pmol/l on day 15 postpartum (n = 7). Plasma kisspeptin IR and hCG concentrations in patients with malignant GTN were elevated at presentation and fell during and after treatment with chemotherapy in each patient (mean plasma kisspeptin IR: prechemotherapy 1,363 +/- 1,076 pmol/l vs. post-chemotherapy <2 pmol/l, P < 0.0001; mean plasma hCG: prechemotherapy 227,191 +/- 152,354 U/l vs. postchemotherapy 2 U/l, P < 0.0001). Plasma kisspeptin IR strongly positively correlated with plasma hCG levels (r(2) = 0.99, P < 0.0001). Our results suggest that measurement of plasma kisspeptin IR may be a novel tumor marker in patients with malignant GTN.


Subject(s)
Biomarkers, Tumor/blood , Trophoblastic Neoplasms/blood , Tumor Suppressor Proteins/blood , Uterine Neoplasms/blood , Adult , Antineoplastic Agents/therapeutic use , Chorionic Gonadotropin/blood , Chromatography, Liquid , Female , Humans , Kisspeptins , Pregnancy , Trophoblastic Neoplasms/drug therapy , Uterine Neoplasms/drug therapy
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