Vasopressin, also known as antidiuretic hormone (ADH), is a peptide hormone that plays a significant role in water regulation and osmoregulation in horses. It is primarily produced in the hypothalamus and released by the posterior pituitary gland. Vasopressin acts on the kidneys to promote water reabsorption, thereby influencing urine concentration and maintaining body fluid balance. It also has vasoconstrictive properties, affecting blood pressure regulation. This page compiles peer-reviewed research studies and scholarly articles that explore the physiological functions, regulatory mechanisms, and clinical implications of vasopressin in equine health and disease.
Lv K, Yang Y, Li Q, Chen R, Deng L, Zhang Y, Jiang N.Horse's milk, with a high nutritional value and few allergenic proteins, could substitute cow's milk for infant consumption. Herein, a label-free, proteomic method was used to identify and compare milk fat globule membrane (MFGM) and whey proteins from three different horse breeds: Selle Français (SF), Welsh pony (WP), and Tieling Draft Horse (TDH). In MFGMs, 16 (SF), 66 (WP), and 45 (TDH) unique proteins were identified, which are involved in the endocytosis, ribosome, and staphylococcus aureus infection pathways, respectively. In whey, 31 (SF), 75 (WP), and 23 (TDH) unique proteins were ide...
Schnuelle ML, Hopster K, Toribio RE, Hurcombe SD.To compare the effects of 7.2% hypertonic and 0.9% isotonic saline (sodium chloride) solutions on cardiovascular parameters and plasma arginine vasopressin (AVP) concentrations in healthy, isoflurane-anesthetized horses. Methods: 8 healthy horses. Methods: In a prospective, randomized, crossover study, horses were anesthetized with isoflurane twice with a 14-day washout period between anesthetic episodes. While anesthetized, horses received a bolus (4 mL/kg) of 7.2% hypertonic saline solution (HS) or 0.9% isotonic saline solution (IS). Heart rate; systolic, mean, and diastolic arterial blood p...
Lee G, Yoon M.Oxytocin (OXT) and vasopressin (AVP) have been associated with social interaction and affiliative behavior in animals. Additionally, AVP is known to affect socially aggressive behavior. In addition, serotonin has an association with aggressive behaviors. The objectives of this study were (1) to evaluate OXT, AVP, and serotonin concentrations in the plasma of horses of different breeds, sexes, and ages and (2) to determine if the neurotransmitters are associated with horse docility and friendliness. This study was performed at Sangju International Equestrian Center. Blood samples were collected...
Borchers A, Magdesian KG, Schenck PA, Kass PH.Vasopressin dysregulation occurs in critically ill human patients and in neonatal foals. Limited data about serial plasma vasopressin dynamics exist in sick neonatal foals. Objective: To evaluate serial plasma arginine vasopressin (AVP) concentrations in sick neonatal foals. Methods: Prospective, longitudinal clinical study. Methods: Plasma samples were collected from 7 healthy and 26 sick foals before and after initial fluid resuscitation and 12, 24, 36, 48 and 96 h after presentation. Foals with a modified sepsis score ≥ 11 were considered septic. Results: Admission AVP was increased in se...
Veronesi MC, Tosi U, Villani M, Govoni N, Faustini M, Kindahl H, Madej A, Carluccio A.This experiment was designed to determine the effects of sexual stimulation on plasma concentrations of oxytocin (OT), vasopressin (VP), 15-ketodihydro-PGF(2alpha) (PG-metabolite), luteinizing hormone (LH), testosterone (T), estrone sulfate (ES), and cortisol (C) in stallions. Semen samples were collected from 14 light horse stallions (Equus caballus) of proven fertility using a Missouri model artificial vagina. Blood samples were collected at 15, 12, 9, 6, and 3 min before estrous mare exposure, at erection, at ejaculation, and at 3, 6, and 9 min after ejaculation. Afterwards, blood sampling ...
Valverde A, Giguère S, Sanchez LC, Shih A, Ryan C.To determine the effects of dobutamine, norepinephrine, and vasopressin on cardiovascular function and gastric mucosal perfusion in anesthetized foals during isoflurane-induced hypotension. Methods: 6 foals that were 1 to 5 days of age. Methods: 6 foals received 3 vasoactive drugs with at least 24 hours between treatments. Treatments consisted of dobutamine (4 and 8 Sang/kg/min), norepinephrine (0.3 and 1.0 Sang/kg/min), and vasopressin (0.3 and 1.0 mU/kg/min) administered IV. Foals were maintained at a steady hypotensive state induced by a deep level of isoflurane anesthesia for 30 minutes, a...
O'Connor SJ, Gardner DS, Ousey JC, Holdstock N, Rossdale P, Edwards CM, Fowden AL, Giussani DA.The aims of this study were to compare and contrast the development of the cardiac baroreflex and endocrine responses to acute hypotensive stress in healthy newborn pony foals and lambs during the first two weeks of postnatal life. Methods: Under general anaesthesia, seven Welsh pony foals and six Welsh Mountain lambs were catheterised with hind limb artery and vein catheters. Following post-surgical recovery, at 1 week and 2 weeks of age, blood pressures of the animals were raised and lowered acutely by intravenous infusion of phenylephrine and sodium nitroprusside, respectively. During hypot...
The Journal of physiologyMarch 24, 2005
Volume 565, Issue Pt 3 1019-1030 doi: 10.1113/jphysiol.2004.078469
Giussani DA, Forhead AJ, Fowden AL.In mammals, the mechanisms regulating an increase in fetal arterial blood pressure with advancing gestational age remain unidentified. In all species studied to date, the prepartum increase in fetal plasma cortisol has an important role in the maturation of physiological systems essential for neonatal survival. In the horse, the prepartum elevation in fetal cortisol and arterial blood pressure are delayed relative to other species. Hence, the mechanisms governing the ontogenic increase in arterial blood pressure in the horse fetus may mature much closer to term than in other fetal animals. In ...
Hada T, Onaka T, Takahashi T, Hiraga A, Yagi K.This study investigated the effects of novelty stress on neuroendocrine activities and running performance in Thoroughbred horses. First, to examine the neuroendocrine responses to novelty stress, we exposed horses to two types of novel environmental stimuli (audiovisual or novel field stimuli). After the stimuli, plasma concentrations of vasopressin, catecholamines and adrenocorticotropin (ACTH), as well as heart rates, were significantly increased in each experiment. Second, we investigated neuroendocrine activities during incremental exercise. Plasma concentrations of vasopressin, catechola...
Alexander SL, Irvine CH.The primary aim of this study was to define the secretory dynamics of oxytocin and vasopressin in pituitary venous effluent from ambulatory horses during acute endotoxaemia, a stimulus that may release both hormones. Our secondary aim was to investigate the role of oxytocin in regulating adrenocorticotropic hormone (ACTH) secretion by comparing oxytocin, vasopressin, corticotropin-releasing hormone (CRH) and ACTH secretory profiles during endotoxaemia and by monitoring the ACTH response to oxytocin administration. Pituitary venous blood was collected nonsurgically continuously and divided into...
Mulligan RS, Livesey JH, Evans MJ, Ellis MJ, Donald RA.It has been suggested that atrial natriuretic peptide (ANP) is the long-sought inhibitor of corticotropin (ACTH) secretion, but the evidence is conflicting. We have examined the effect of ANP and C-type natriuretic peptide (CNP) on the secretion of ACTH by perifused equine pituitary cells in an in vitro milieu intended to mimic the in vivo milieu in the horse. Corticotropin-releasing hormone (20 pM) and cortisol (0 or 100 nM) were perifused continuously and 7 pulses of arginine vasopressin (AVP; 10 nM) applied for 5 min at 30-min intervals. ANP (1 nM) or CNP (1 nM) were perifused continuously ...
Sneddon JC, Van Der Walt J, Mitchell G, Hammer S, Taljaard JJ.We have investigated the change in plasma vasopressin and aldosterone concentrations in Namib (desert-adapted) and in control horses from a subtropical region, during an acute 12% dehydration and during rehydration, while food was available. During dehydration, vasopressin concentrations increased significantly in both groups of horses, but the increase was significantly greater in Namib horses than in control horses. During rehydration, vasopressin levels fell, but fell significantly less in Namib horses. The change in vasopressin concentration correlated significantly with plasma osmolality ...
Irvine CH, Alexander SL, Donald RA.Arginine vasopressin (AVP) is released in response to changes in blood osmolality and is also a putative secretagogue for ACTH. However, it is unclear whether osmotically generated increases in AVP in the physiological range influence ACTH secretion. We have studied this question using our unique noninvasive technique for collecting pituitary venous blood in six normal conscious horses that received an iv infusion of hypertonic saline (HS; 5%, 0.07 ml/kg.min) for 45-60 min. Pituitary and jugular venous samples were collected every 5 min for 40 min before, during, and for 20 min after HS. Durin...
Houpt KA, Thornton SN, Allen WR.Six pony mares deprived of water for 24 hours showed significant increases in plasma vasopressin (2.8 pg/ml) and osmolality (9 mosmol/kg). When water was made available the ponies drank rapidly (5 of 6 drank to satiety within 90 seconds) and corrected their fluid deficits precisely. Vasopressin did not return to predehydration levels until osmolality did after 15 minutes of access to water. The horse differs from rodents and humans, but is similar to pigs in that vasopressin levels do not fall before osmolality returns to normal. Oropharyngeal factors, therefore, may not be as important in vas...
Livesey JH, Donald RA, Irvine CH, Redekopp C, Alexander SL.Plasma ACTH, arginine vasopressin (AVP), and alpha MSH were measured in pituitary venous effluent at 5-min intervals from five unanesthetized horses during cortisol infusion and after an iv bolus of AVP or ovine (o) CRF. In control experiments (no hormone) there was a significant overall correlation between the timing of concentration changes in ACTH and alpha MSH. Cortisol infusion increased jugular cortisol levels by 70% and was associated with a reduction in mean ACTH, AVP, and alpha MSH secretion rates and ACTH peak secretion rate, but did not alter the observed pulse frequencies of these ...
Redekopp C, Irvine CH, Donald RA, Livesey JH, Sadler W, Nicholls MG, Alexander SL, Evans MJ.Plasma ACTH, arginine vasopressin (AVP), and catecholamines were measured at 5-min intervals in the pituitary venous effluent of the unanesthetized horse. Pulses of ACTH and AVP were found to be surprisingly brief (usually of less than 10-min duration) and frequent (averaging between 15-25 min). A highly significant relationship in the changes in concentration of these two hormones was demonstrated (P less than 0.0002) both at rest and after a mild hypoglycemic stimulus. Although there was also a significant correlation (P less than 0.005) between simultaneous plasma ACTH and AVP values the pu...
Valverde A, Giguère S, Sanchez LC, Shih A, Ryan C.To determine the effects of dobutamine, norepinephrine, and vasopressin on cardiovascular function and gastric mucosal perfusion in anesthetized foals during isoflurane-induced hypotension. Methods: 6 foals that were 1 to 5 days of age. Methods: 6 foals received 3 vasoactive drugs with at least 24 hours between treatments. Treatments consisted of dobutamine (4 and 8 Sang/kg/min), norepinephrine (0.3 and 1.0 Sang/kg/min), and vasopressin (0.3 and 1.0 mU/kg/min) administered IV. Foals were maintained at a steady hypotensive state induced by a deep level of isoflurane anesthesia for 30 minutes, a...
The Journal of physiologyMarch 24, 2005
Volume 565, Issue Pt 3 1019-1030 doi: 10.1113/jphysiol.2004.078469
Giussani DA, Forhead AJ, Fowden AL.In mammals, the mechanisms regulating an increase in fetal arterial blood pressure with advancing gestational age remain unidentified. In all species studied to date, the prepartum increase in fetal plasma cortisol has an important role in the maturation of physiological systems essential for neonatal survival. In the horse, the prepartum elevation in fetal cortisol and arterial blood pressure are delayed relative to other species. Hence, the mechanisms governing the ontogenic increase in arterial blood pressure in the horse fetus may mature much closer to term than in other fetal animals. In ...
Hada T, Onaka T, Takahashi T, Hiraga A, Yagi K.This study investigated the effects of novelty stress on neuroendocrine activities and running performance in Thoroughbred horses. First, to examine the neuroendocrine responses to novelty stress, we exposed horses to two types of novel environmental stimuli (audiovisual or novel field stimuli). After the stimuli, plasma concentrations of vasopressin, catecholamines and adrenocorticotropin (ACTH), as well as heart rates, were significantly increased in each experiment. Second, we investigated neuroendocrine activities during incremental exercise. Plasma concentrations of vasopressin, catechola...
Redekopp C, Irvine CH, Donald RA, Livesey JH, Sadler W, Nicholls MG, Alexander SL, Evans MJ.Plasma ACTH, arginine vasopressin (AVP), and catecholamines were measured at 5-min intervals in the pituitary venous effluent of the unanesthetized horse. Pulses of ACTH and AVP were found to be surprisingly brief (usually of less than 10-min duration) and frequent (averaging between 15-25 min). A highly significant relationship in the changes in concentration of these two hormones was demonstrated (P less than 0.0002) both at rest and after a mild hypoglycemic stimulus. Although there was also a significant correlation (P less than 0.005) between simultaneous plasma ACTH and AVP values the pu...
Irvine CH, Alexander SL, Donald RA.Arginine vasopressin (AVP) is released in response to changes in blood osmolality and is also a putative secretagogue for ACTH. However, it is unclear whether osmotically generated increases in AVP in the physiological range influence ACTH secretion. We have studied this question using our unique noninvasive technique for collecting pituitary venous blood in six normal conscious horses that received an iv infusion of hypertonic saline (HS; 5%, 0.07 ml/kg.min) for 45-60 min. Pituitary and jugular venous samples were collected every 5 min for 40 min before, during, and for 20 min after HS. Durin...
Veronesi MC, Tosi U, Villani M, Govoni N, Faustini M, Kindahl H, Madej A, Carluccio A.This experiment was designed to determine the effects of sexual stimulation on plasma concentrations of oxytocin (OT), vasopressin (VP), 15-ketodihydro-PGF(2alpha) (PG-metabolite), luteinizing hormone (LH), testosterone (T), estrone sulfate (ES), and cortisol (C) in stallions. Semen samples were collected from 14 light horse stallions (Equus caballus) of proven fertility using a Missouri model artificial vagina. Blood samples were collected at 15, 12, 9, 6, and 3 min before estrous mare exposure, at erection, at ejaculation, and at 3, 6, and 9 min after ejaculation. Afterwards, blood sampling ...
Lee G, Yoon M.Oxytocin (OXT) and vasopressin (AVP) have been associated with social interaction and affiliative behavior in animals. Additionally, AVP is known to affect socially aggressive behavior. In addition, serotonin has an association with aggressive behaviors. The objectives of this study were (1) to evaluate OXT, AVP, and serotonin concentrations in the plasma of horses of different breeds, sexes, and ages and (2) to determine if the neurotransmitters are associated with horse docility and friendliness. This study was performed at Sangju International Equestrian Center. Blood samples were collected...
Livesey JH, Donald RA, Irvine CH, Redekopp C, Alexander SL.Plasma ACTH, arginine vasopressin (AVP), and alpha MSH were measured in pituitary venous effluent at 5-min intervals from five unanesthetized horses during cortisol infusion and after an iv bolus of AVP or ovine (o) CRF. In control experiments (no hormone) there was a significant overall correlation between the timing of concentration changes in ACTH and alpha MSH. Cortisol infusion increased jugular cortisol levels by 70% and was associated with a reduction in mean ACTH, AVP, and alpha MSH secretion rates and ACTH peak secretion rate, but did not alter the observed pulse frequencies of these ...
Alexander SL, Irvine CH.The primary aim of this study was to define the secretory dynamics of oxytocin and vasopressin in pituitary venous effluent from ambulatory horses during acute endotoxaemia, a stimulus that may release both hormones. Our secondary aim was to investigate the role of oxytocin in regulating adrenocorticotropic hormone (ACTH) secretion by comparing oxytocin, vasopressin, corticotropin-releasing hormone (CRH) and ACTH secretory profiles during endotoxaemia and by monitoring the ACTH response to oxytocin administration. Pituitary venous blood was collected nonsurgically continuously and divided into...
Borchers A, Magdesian KG, Schenck PA, Kass PH.Vasopressin dysregulation occurs in critically ill human patients and in neonatal foals. Limited data about serial plasma vasopressin dynamics exist in sick neonatal foals. Objective: To evaluate serial plasma arginine vasopressin (AVP) concentrations in sick neonatal foals. Methods: Prospective, longitudinal clinical study. Methods: Plasma samples were collected from 7 healthy and 26 sick foals before and after initial fluid resuscitation and 12, 24, 36, 48 and 96 h after presentation. Foals with a modified sepsis score ≥ 11 were considered septic. Results: Admission AVP was increased in se...
Mulligan RS, Livesey JH, Evans MJ, Ellis MJ, Donald RA.It has been suggested that atrial natriuretic peptide (ANP) is the long-sought inhibitor of corticotropin (ACTH) secretion, but the evidence is conflicting. We have examined the effect of ANP and C-type natriuretic peptide (CNP) on the secretion of ACTH by perifused equine pituitary cells in an in vitro milieu intended to mimic the in vivo milieu in the horse. Corticotropin-releasing hormone (20 pM) and cortisol (0 or 100 nM) were perifused continuously and 7 pulses of arginine vasopressin (AVP; 10 nM) applied for 5 min at 30-min intervals. ANP (1 nM) or CNP (1 nM) were perifused continuously ...
O'Connor SJ, Gardner DS, Ousey JC, Holdstock N, Rossdale P, Edwards CM, Fowden AL, Giussani DA.The aims of this study were to compare and contrast the development of the cardiac baroreflex and endocrine responses to acute hypotensive stress in healthy newborn pony foals and lambs during the first two weeks of postnatal life. Methods: Under general anaesthesia, seven Welsh pony foals and six Welsh Mountain lambs were catheterised with hind limb artery and vein catheters. Following post-surgical recovery, at 1 week and 2 weeks of age, blood pressures of the animals were raised and lowered acutely by intravenous infusion of phenylephrine and sodium nitroprusside, respectively. During hypot...
Sneddon JC, Van Der Walt J, Mitchell G, Hammer S, Taljaard JJ.We have investigated the change in plasma vasopressin and aldosterone concentrations in Namib (desert-adapted) and in control horses from a subtropical region, during an acute 12% dehydration and during rehydration, while food was available. During dehydration, vasopressin concentrations increased significantly in both groups of horses, but the increase was significantly greater in Namib horses than in control horses. During rehydration, vasopressin levels fell, but fell significantly less in Namib horses. The change in vasopressin concentration correlated significantly with plasma osmolality ...
Schnuelle ML, Hopster K, Toribio RE, Hurcombe SD.To compare the effects of 7.2% hypertonic and 0.9% isotonic saline (sodium chloride) solutions on cardiovascular parameters and plasma arginine vasopressin (AVP) concentrations in healthy, isoflurane-anesthetized horses. Methods: 8 healthy horses. Methods: In a prospective, randomized, crossover study, horses were anesthetized with isoflurane twice with a 14-day washout period between anesthetic episodes. While anesthetized, horses received a bolus (4 mL/kg) of 7.2% hypertonic saline solution (HS) or 0.9% isotonic saline solution (IS). Heart rate; systolic, mean, and diastolic arterial blood p...
Houpt KA, Thornton SN, Allen WR.Six pony mares deprived of water for 24 hours showed significant increases in plasma vasopressin (2.8 pg/ml) and osmolality (9 mosmol/kg). When water was made available the ponies drank rapidly (5 of 6 drank to satiety within 90 seconds) and corrected their fluid deficits precisely. Vasopressin did not return to predehydration levels until osmolality did after 15 minutes of access to water. The horse differs from rodents and humans, but is similar to pigs in that vasopressin levels do not fall before osmolality returns to normal. Oropharyngeal factors, therefore, may not be as important in vas...
Lv K, Yang Y, Li Q, Chen R, Deng L, Zhang Y, Jiang N.Horse's milk, with a high nutritional value and few allergenic proteins, could substitute cow's milk for infant consumption. Herein, a label-free, proteomic method was used to identify and compare milk fat globule membrane (MFGM) and whey proteins from three different horse breeds: Selle Français (SF), Welsh pony (WP), and Tieling Draft Horse (TDH). In MFGMs, 16 (SF), 66 (WP), and 45 (TDH) unique proteins were identified, which are involved in the endocytosis, ribosome, and staphylococcus aureus infection pathways, respectively. In whey, 31 (SF), 75 (WP), and 23 (TDH) unique proteins were ide...
