Development of insulin and proinsulin secretion in newborn pony foals.
Abstract: At birth, the endocrine pancreas must assume a glucoregulatory role if the neonate is to survive the transition from parenteral to enteral nutrition. In species like the horse, neonatal hypoglycaemia is common, which suggests that the glucoregulatory mechanisms are not always fully competent at birth. Hence, this study examined pancreatic beta cell function in newborn foals during nutritional adaptation over the first 10 days post partum. Over a 48 h period at three time intervals after birth (days 1-2, 5-6 and 9-10 post partum), the beta cell responses to suckling and to intravenous administration of glucose, arginine and saline were measured in seven normal pony foals. Basal plasma concentrations of proinsulin, but not insulin or glucose, increased significantly between days 1 and 10. Suckling caused a gradual increase in plasma glucose, which was accompanied by a significant increase in plasma insulin concentrations 15 min after the onset of suckling on days 5 and 9, but not day 1. There was no significant change in plasma proinsulin concentrations in response to suckling at any age. At all ages studied, glucose and arginine administration stimulated an increase in the plasma concentrations of insulin and proinsulin; these beta cell responses did not change significantly with postnatal age. The insulin responses to glucose were significantly greater than those of arginine at each time period. Glucose clearance was significantly slower on day 1 than subsequently. Proinsulin and glucose, but not insulin, concentrations decreased significantly after saline administration at all three ages. At each time period, there was a significant positive relationship between the plasma insulin and proinsulin concentrations, the slope of which was significantly shallower on days 1-2 than subsequently. These results show that equine beta cells are responsive to glucose and arginine and release both insulin and proinsulin during the immediate postnatal period. They also suggest that newborn foals may be insulin resistant on the first day after birth.
Publication Date: 2004-06-03 PubMed ID: 15171695DOI: 10.1677/joe.0.1810469Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The study examines how the insulin and proinsulin secretion functions develop in newborn horses during the first 10 days after birth, using a series of tests to measure how these mechanisms respond to varying stimuli. The research results suggest that newborn horses might exhibit insulin resistance on the day they are born.
Research Methodology
- The researchers studied the function of pancreatic beta cells, the cells responsible for insulin and proinsulin secretion, in newborn foals as they transition to enteral (through the digestive tract) nutrition in the first 10 days after birth.
- They performed their tests at three different intervals, 1-2 days, 5-6 days, and 9-10 days after birth, subjecting the foals to varying stimuli, such as suckling and the intravenous administration of glucose, arginine, and saline.
Research Findings
- The researchers found a progressive elevation in proinsulin levels, but the glucose and insulin levels didn’t register a significant change between days 1 and 10.
- The study revealed that suckling led to the gradual increase of plasma glucose and a significant increase in insulin levels after 15 minutes on the 5th and 9th days.
- The stimulation of insulin and proinsulin production and release by glucose and arginine was observed at all three intervals, suggesting that the beta cells were responsive to these substances from birth.
- Insulin responses to glucose were significantly higher than to arginine at every interval measured.
- Glucose clearance (the rate at which glucose is removed from the bloodstream) was notably slower on the first day, indicating a possible insulin resistance.
- Salt injection significantly decreased the proinsulin and glucose concentrations, though it didn’t significantly affect insulin levels.
- The data also revealed a positive correlation between plasma insulin and proinsulin concentrations, though this relationship was not as pronounced on days 1-2.
Conclusion
- In conclusion, the study reveals that newborn foals’ pancreatic beta cells are indeed responsive to glucose and arginine, secreting insulin and proinsulin right after birth.
- It also suggests that newborn foals may exhibit insulin resistance on their birth day, highlighting the need for monitoring their glucose levels for effective glucoregulation.
Cite This Article
APA
Holdstock NB, Allen VL, Bloomfield MR, Hales CN, Fowden AL.
(2004).
Development of insulin and proinsulin secretion in newborn pony foals.
J Endocrinol, 181(3), 469-476.
https://doi.org/10.1677/joe.0.1810469 Publication
Researcher Affiliations
- Department of Clinical Veterinary Medicine, University of Cambridge, Cambridge CB3 OES, UK. nbh10@cam.ac.uk
MeSH Terms
- Animal Nutritional Physiological Phenomena
- Animals
- Animals, Newborn / physiology
- Arginine / pharmacology
- Enteral Nutrition / veterinary
- Glucose / pharmacology
- Horses / physiology
- Insulin / metabolism
- Insulin Secretion
- Islets of Langerhans / drug effects
- Islets of Langerhans / physiology
- Proinsulin / metabolism
- Stimulation, Chemical
Citations
This article has been cited 7 times.- Martinez RE, Leatherwood JL, Bradbery AN, Paris BL, Hammer CJ, Kelley D, Bazer FW, Wu G. Evaluation of dietary arginine supplementation to increase placental nutrient transporters in aged mares.. Transl Anim Sci 2023 Jan;7(1):txad058.
- Kinsella HM, Hostnik LD, Snyder HA, Mazur SE, Kamr AM, Burns TA, Mossbarger JC, Toribio RE. Comparison of insulin sensitivity between healthy neonatal foals and horses using minimal model analysis.. PLoS One 2022;17(1):e0262584.
- Kinsella HM, Hostnik LD, Rings LM, Swink JM, Burns TA, Toribio RE. Glucagon, insulin, adrenocorticotropic hormone, and cortisol in response to carbohydrates and fasting in healthy neonatal foals.. J Vet Intern Med 2021 Jan;35(1):550-559.
- Rings LM, Swink JM, Dunbar LK, Burns TA, Toribio RE. Enteroinsular axis response to carbohydrates and fasting in healthy newborn foals.. J Vet Intern Med 2019 Nov;33(6):2752-2764.
- Robles M, Couturier-Tarrade A, Derisoud E, Geeverding A, Dubois C, Dahirel M, Aioun J, Prezelin A, Calvez J, Richard C, Wimel L, Chavatte-Palmer P. Effects of dietary arginine supplementation in pregnant mares on maternal metabolism, placental structure and function and foal growth.. Sci Rep 2019 Apr 23;9(1):6461.
- Navas de Solis C, Foreman JH. Transient diabetes mellitus in a neonatal Thoroughbred foal.. J Vet Emerg Crit Care (San Antonio) 2010 Dec;20(6):611-5.
- Kirovski D, Lazarević M, Baricević-Jones I, Nedić O, Masnikosa R, Nikolie JA. Effects of peroral insulin and glucose on circulating insulin-like growth factor-1, its binding proteins and thyroid hormones in neonatal calves.. Can J Vet Res 2008 Apr;72(3):253-8.
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