Explanipedia

Prolactin and heat stress; focus on domestic ruminants Open

Iain J. Clarke, Frank R. Dunshea, Surinder S. Chauhan · 2025

Prolactin has traditionally been associated with milk production, but recent studies identify prolactin as having many other functions. These include a role in pelage growth, sweating, immune function, metabolism, and water/electrolyte bal…

Femoral Artery Infusion of αMSH Increases Muscle Thermogenesis and Promotes Glucose Uptake in Ovariectomized Ewes Open

Belinda A. Henry, Michael A. Cowley, Zane B. Andrews, Iain J. Clarke · 2024

The melanocortin system is fundamental to neural control of energy balance and long-term weight regulation. Recent evidence shows that melanocortins also act at peripheral tissues to regulate metabolism, independent of the brain or the sym…

Triiodothyronine supplementation in a sheep model of intensive care Open

Matthew J. Maiden, David J. Torpy, Guy Ludbrook, Iain J. Clarke, Binila Chacko , et al. · 2024

Triiodothyronine (T3) concentrations in plasma decrease during acute illness and it is unclear if this contributes to disease. Clinical and laboratory studies of T3 supplementation in disease have revealed little or no effect. It is uncert…

Impact of heat stress on ruminant livestock production and meat quality, and strategies for amelioration Open

Surinder S. Chauhan, Minghao Zhang, Richard Osei-Amponsah, Iain J. Clarke, Veerasamy Sejian , et al. · 2023

Climate change will continue to accentuate the negative impact of heat stress (HS) on ruminant livestock production, compromising animal welfare and meat quality. Mitigation strategies, including providing shade on farms, modifications of …

The GLP-1 agonist, exendin-4, stimulates LH secretion in female sheep Open

Elizabeth M Simpson, Iain J. Clarke, Christopher Scott, Cyril Stephen, Alexandra Rao , et al. · 2023

Our previous studies showed that microinjection into the median eminence of the sheep of glucagon-like peptide- 1 (GLP-1) or its receptor agonist exendin-4 stimulates luteinising hormone (LH) secretion, but it is unknown whether the same e…

Hexapeptides from mammalian inhibitory hormone hunt activate and inactivate nematode reproduction Open

John E Hart, Sharad Mohan, Keith Davies, Ben Ferneyhough, Iain J. Clarke , et al. · 2022

Background Biopurification has been used to disclose an evolutionarily conserved inhibitory reproductive hormone involved in tissue mass determination. A (rat) bioassay-guided physicochemical fractionation using ovine materials yielded via…

Response to kisspeptin and gonadotropin-releasing hormone agonist administration in Holstein-Friesian dairy heifers with positive or negative genetic merit for fertility traits Open

Holly Flay, C.B. Reed, B. Kuhn‐Sherlock, C.V.C. Phyn, C.R. Burke , et al. · 2022

Previous research has identified that Holstein-Friesian dairy heifers with positive (POS) genetic merit for fertility traits (FertBV) reach puberty earlier than heifers with negative (NEG) FertBV. The hypothalamus-pituitary-gonadal (HPG) a…

Kiss1 expression in the hypothalamic arcuate nucleus is lower in dairy cows of reduced fertility Open

Iain J. Clarke, C.B. Reed, C.R. Burke, Qun Li, S. Meier · 2022

We tested the hypothesis that divergent genetic merit for fertility of dairy cows is due to aberrant reproductive neuroendocrine function. The kisspeptin status of non-pregnant cows of either positive (POS) or negative (NEG) breeding value…

Hexapeptides from a mammalian inhibitory hormone activate and inactivate nematode reproduction Open

John E Hart, Sharad Mohan, Keith Davies, Ben Ferneyhough, Iain J. Clarke , et al. · 2021

Background Biopurification has been used to disclose an evolutionarily conserved inhibitory reproductive hormone involved in tissue mass determination. A (rat) bioassay-guided physicochemical fractionation using ovine materials yielded via…

The melanocortin pathway and energy homeostasis: From discovery to obesity therapy Open

Giles S.H. Yeo, Daniela Herrera Moro Chao, Anna‐Maria Siegert, Zoe M. Koerperich, Mark D. Ericson , et al. · 2021

Glucagon-like peptide-1 control of GnRH secretion in female sheep Open

Leila Arbabi, Qun Li, Belinda A. Henry, Iain J. Clarke · 2021

The role of glucagon-like peptide-1 (GLP-1) on gonadotropin-releasing hormone (GnRH) secretion was investigated in ovariectomised (OVX) ewes, in which GnRH and luteinising hormone (LH) secretion had been restrained by treatment with oestro…

Comparative Assessment of Thermotolerance in Dorper and Second-Cross (Poll Dorset/Merino × Border Leicester) Lambs Open

Aleena Joy, Frank R. Dunshea, B. J. Leury, Kristy DiGiacomo, Iain J. Clarke , et al. · 2020

The objective of this study was to compare the thermotolerance of second-cross (SC; Poll Dorset × Merino × Border Leicester) and Dorper lambs. Dorper and SC lambs (4–5 months of age) were subjected to cyclic heat stress (HS) (28–40 °C). Th…

Effect of sex and sex steroids on brown adipose tissue heat production in humans Open

John‐Paul Fuller‐Jackson, Aimee L. Dordevic, Iain J. Clarke, Belinda A. Henry · 2020

Objective: Retrospective studies suggest that women have more active brown adipose tissue (BAT) than men, but little is known of the effect of fluctuating sex steroids across the menstrual cycle on thermogenesis in women. Design: To charac…

Resilience of Small Ruminants to Climate Change and Increased Environmental Temperature: A Review Open

Aleena Joy, Frank R. Dunshea, B. J. Leury, Iain J. Clarke, Kristy DiGiacomo , et al. · 2020

Climate change is a major global threat to the sustainability of livestock systems. Climatic factors such as ambient temperature, relative humidity, direct and indirect solar radiation and wind speed influence feed and water availability, …

The Effect of Heat Stress on Respiratory Alkalosis and Insulin Sensitivity in Cinnamon Supplemented Pigs Open

Jeremy J. Cottrell, John B. Furness, Udani A. Wijesiriwardana, Mitchell Ringuet, Fan Liu , et al. · 2020

With increases in the frequency, intensity and duration of heat waves forecast plus expansion of tropical agriculture, heat stress (HS) is both a current and an emerging problem. As cinnamon has been shown to increase insulin sensitivity, …

Differences in Thermoregulatory Responses between Dorper and Second Cross Lambs to Heat Stress Challenges Open

Aleena Joy, Frank R. Dunshea, Brain J. Leury, Kristy DiGiacomo, Iain J. Clarke , et al. · 2020

We compared the thermotolerance of Dorper (D) and second cross (SC) (Poll Dorset x Merino/Border Leicester) lambs by assessing physiological and biochemical responses. After acclimatization, 4–5 month old lambs of each breed were exposed t…

Adaptive and Productive Sheep Breed for Changing Climate Open

Surinder S. Chauhan, Minghao Zhang, Aleena Joy, Richard Osei-Amponsah, B. J. Leury , et al. · 2020

Sheep in semi-arid environments are likely to be affected by warming environment due to climate change. To identify genotypes best suited to warmer climates we assessed thermotolerance and meat quality of 5 female sheep of each of 4 breeds…

Expression of genes for Kisspeptin ( KISS1 ), Neurokinin B ( TAC3 ), Prodynorphin ( PDYN ), and gonadotropin inhibitory hormone ( RFRP ) across natural puberty in ewes Open

Qun Li, J. T. Smith, Belinda A. Henry, Alexandra Rao, Alda Pereira , et al. · 2020

Expression of particular genes in hypothami of ewes was measured across the natural pubertal transition by in situ hybridization. The ewes were allocated to three groups (n = 4); prepubertal, postpubertal and postpubertally gonadectomized …

Epitope mapping of an uncertain endogenous antigen implies secretogranin II peptide splicing Open

David Howlett, Iain J. Clarke, Russell P. Newton, John E Hart · 2019

Background: The search for a tissue-mass reducing reproductive hormone involved a bioassay-guided physicochemical fractionation of sheep blood plasma. This brought forth a candidate protein whose apparent mass on gels and in mass spectrome…

Genetic Selection for Thermotolerance in Ruminants Open

Richard Osei-Amponsah, Surinder S. Chauhan, B. J. Leury, Long Cheng, Brendan Cullen , et al. · 2019

Variations in climatic variables (temperature, humidity and solar radiation) negatively impact livestock growth, reproduction, and production. Heat stress, for instance, is a source of huge financial loss to livestock production globally. …

Epitope mapping of an uncertain endogenous antigen implies secretogranin II peptide splicing Open

David Howlett, Iain J. Clarke, Russell P. Newton, John E Hart · 2019

Background: The search for a tissue-mass reducing reproductive hormone involved a bioassay-guided physicochemical fractionation of sheep blood plasma. This brought forth a candidate protein whose apparent mass on gels and in mass spectrome…

Perennial Ryegrass Alkaloids Increase Respiration Rate and Decrease Plasma Prolactin in Merino Sheep under Both Thermoneutral and Mild Heat Conditions Open

Michelle Lauren Elizabeth Henry, Stuart Kemp, Iain J. Clarke, Frank R. Dunshea, B. J. Leury · 2019

A study was undertaken to determine the effects of feeding two levels of perennial ryegrass alkaloids (nil vs. moderate) under two climatic conditions. Alkaloids were fed via endophyte-infected perennial ryegrass seed and hay. Twenty-four …

Control of GnRH secretion Open

Iain J. Clarke · 2019

Regulation of the secretion of FSH in domestic ruminants Open

J. K. Findlay, Iain J. Clarke · 2019

Peripheral and intragonadal actions of inhibin-related peptides Open

JK Findlay, Iain J. Clarke, MR Luck, RJ Rodgers, L Shukovski , et al. · 2019

Negative feedback regulation of the secretion and actions of GnRH in male ruminants Open

A.J. Tilbrook, Iain J. Clarke · 2019

The roles of testicular hormones in the negative feedback regulation of the secretion and actions of GnRH in male domestic ruminants are reviewed, concentrating mainly on research conducted with rams. Testicular steroids have major feedbac…

The role of kisspeptin and gonadotropin inhibitory hormone (GnIH) in the seasonality of reproduction in sheep Open

Iain J. Clarke, J.K. Smith · 2019

Sheep are seasonal breeders and reproductive status is controlled by photoperiod. Recent recognition of the significant role for kisspeptin and gonadotropin inhibitory hormone (GnIH) in the regulation of gonadotropin releasing hormone (GnR…

Inhibin in rams Open

Iain J. Clarke, A.J. Tilbrook, D.C. Galloway, C.R. Earl, JK Findlay , et al. · 2019

MON-LB016 Sex and Sex Steroid Effects on Brown Adipose Tissue Temperature in Healthy Humans Open

John‐Paul Fuller‐Jackson, Aimee L. Dordevic, Helen Truby, Iain J. Clarke, Belinda A. Henry · 2019

Retrospective studies indicate that women have more brown adipose tissue (BAT) than men. Furthermore, animal studies show that sex steroids modulate BAT activity, wherein estrogen increases BAT function. We aimed to characterize BAT thermo…

Stimulation of growth hormone by kisspeptin antagonists in ewes Open

J. T. Smith, Antonia K. Roseweir, Michael Millar, Iain J. Clarke, Robert P. Millar · 2018

Kisspeptin signalling is indispensable for fertility, stimulating gonadotropin-releasing hormone (GnRH) secretion and mediating gonadal steroid feedback on GnRH neurons. Moreover, kisspeptin neurons have been implicated in other non-reprod…

Iain J. Clarke YOU? Author Swipe