Vitamin D supplementation enhanced oral glucose tolerance in normoglycemic rats and insulin sensitivity in rats fed high fat emulsion

  • Ifeanyi G. EkeEmail author
  • Chukwunonso K. Ezeasor
  • Aruh O. Anaga
Original Article


Several reports have suggested possible role of vitamin D deficiency in the pathogenesis of both type 1 and 2 diabetes. However, there is no agreement on the level of vitamin D requirement for optimum glycemic control. This work evaluated the effect of vitamin D supplementation on oral glucose tolerance (OGT) and insulin sensitivity, with the aim of determining the possible supplementation rate of vitamin D required for optimum glycemic control. Oral glucose tolerance was evaluated in normoglycemic rats, with vitamin D supplementation (VDS) at the rate of 0.07, 0.14, and 0.35 μg/kg orally for 28 days. Oral glucose tolerance (OGT) was evaluated by administration of 2000 mg/kg glucose/rat orally and blood glucose determined at 30, 60, and 120 min post glucose administration. Insulin sensitivity was evaluated in normoglycemic rats fed high fat emulsion (HFE) at the rate of 5 ml/kg/rat for 10 days and VDS was at the rate of 0.04, 0.05, 0.07, and 0.35 μg/kg for 38 days. Insulin (0.05 u/kg) was injected intraperitoneally to each rat, and blood glucose level determined at 5, 30, 60, and 120 min post insulin administration. Blood glucose of VDS rats was significantly (p < 0.05) lower than the vitamin D restricted group at 120 min. Significantly, (p < 0.05) higher OGT was recorded in the VDS groups. Insulin sensitivity (K) values showed inverse dose dependency with higher K values at lower vitamin D doses. Vitamin D supplementation enhanced glucose tolerance and insulin sensitivity at lower doses.


Vitamin D Supplementation Glucose tolerance Insulin sensitivity High fat emulsion 


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical statement

All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.


  1. Alvarez JA, Ashraf A (2010) Role of vitamin D in insulin sensitivity for glucose homeostasis. Int J Endocrinol 20:351–385Google Scholar
  2. de Boer IH, Tinker LF, Connelly S, Curb JD, Manson JE, Margolis KL, Siscovick DS, Weiss NS (2008) Calcium plus vitamin D supplementation and risk of incident diabetes in the women’s health initiative. Diabetes Care 31:701–707CrossRefPubMedCentralGoogle Scholar
  3. Eke IG, Igwe C, Anaga AO (2014) Vitamin D supplementation attenuated carageenan-induced paw edema and formalin-induced nociception in indomethacin-treated rats. Int J Basic Clin Pharmacol 3:206–2010CrossRefGoogle Scholar
  4. Gulceth HL, Wium C, Birkeland KL (2010) Vitamin D and insulin action and secretion –an overview of current understanding and future perspectives. Eur Endocrinol 6:13–18CrossRefGoogle Scholar
  5. Horlick MF (2007) Vitamin D deficiency. N Engl J Med 357:266–281Google Scholar
  6. Jing A, Wang MY, Zhi MD, Yong-Chun Z, Bao FY (2005) Development of Wistar rat model o f insulin resistance. World J Gastroenterol 11:3675–3679CrossRefGoogle Scholar
  7. Kadowaki S, Norman AW (1984) Dietary vitamin D is essential for normal insulin secretion from the perfused rat pancreas. J Clin Invest 73:759–788CrossRefPubMedCentralGoogle Scholar
  8. Krishna GS, Bubblu T, Amarabalan R (2011) Role of vitamin D in diabetes. J Endocrinol Metab 1:47–56Google Scholar
  9. Liu S, Song Y, Ford ES, Manson JE, Buring JE, Ridker PM (2005) Dietary calcium, vitamin D and the prevalence of metabolic syndrome in middle-aged and older U.S. women. Diabetes Care 28:2926–2932CrossRefGoogle Scholar
  10. National Institute of Health Medline Plus (2011) New recommended daily amounts of vitamin D and calcium. A publication of National Institute of Health and the Friends of National Library of Medicine 5(4):12Google Scholar
  11. Parildar H, Asli DU, Guldeniz AD, Ozlem C, Nilgun GD (2013) Frequency of vitamin D deficiency in pregnant diabetics at Baskent University Hospital Istanbul. Pak J Med Sci 29:15–20PubMedCentralGoogle Scholar
  12. Pitas AG, Harris SS, Stark PC, Dawson-Hughes B (2007) The effect of calcium and vitamin D supplementation on blood glucose and markers of inflammation in non-diabetic adults. Diabetes Care 30:980–986CrossRefGoogle Scholar
  13. Pitas AG, Sun Q, Manson JE, Dawson-Hughes B, Hu FB (2010) Plasma 25-hydroxyvitamin D concentration and the risk of incident type 2 diabetes in women. Diabetes Care 33:202–2023Google Scholar
  14. Pittas AG, Dawson-Hughes B, Li T, Van Dam RM, Willet WC, Manson JE, Hu FB (2006) Vitamin D and calcium intake in relation to type 2 diabetes in women. Diabetes Care 29:650–656CrossRefGoogle Scholar
  15. Rang HP, Dale MM, Rita JM (1996) Pharmacology, 3rd edn. Churchill Livingstone, EdinburghGoogle Scholar
  16. Tarcin O, Yavuz DG, Ozben B, Telli A, Ogunc AV, Yuksel M, Toprak A, Yazici D, Sancak S, Deyneli O, Akalin S (2009) Effect of vitamin D deficiency and replacement on endothelial function in asymptomatic subjects. J Clin Endocrinol Metab 94:4023–4030CrossRefGoogle Scholar
  17. Teegardens D, Donkins SS (2009) Vitamin D: emerging new roles in insulin sensitivity. Nutr Res Rev 22:82–92CrossRefGoogle Scholar

Copyright information

© Springer-Verlag London Ltd., part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of Veterinary Physiology and PharmacologyUniversity of Nigeria NsukkaNsukkaNigeria
  2. 2.Department of Veterinary Pathology and MicrobiologyUniversity of Nigeria NsukkaNsukkaNigeria

Personalised recommendations