Grapefruit juice improves glucose intolerance in streptozotocin-induced diabetes by suppressing hepatic gluconeogenesis.

Hayanga, J.A; Ngubane, S.P.; Murunga, A.N.; Owira, P.M

Grapefruit juice improves glucose intolerance in streptozotocin-induced diabetes by suppressing hepatic gluconeogenesis.

dc.contributor.author	Hayanga, J.A
dc.contributor.author	Ngubane, S.P.
dc.contributor.author	Murunga, A.N.
dc.contributor.author	Owira, P.M
dc.contributor.department	The study was supported by a grant from the Medical Research Council of South African, and there is no conflict of interest to declare.	en_US
dc.date.accessioned	2019-12-18T07:53:47Z
dc.date.available	2019-12-18T07:53:47Z
dc.date.epub	2015-03-20
dc.date.issued	2016-03
dc.description.abstract	Purpose Hypoglycemic effects of grapefruit juice (GFJ) are widely recognized, but the mechanism(s) by which GFJ lowers blood glucose levels have not previously been investigated. Methods Wistar rats [250–300 g body weight (BW)] were divided into eight groups (n = 7). Group 1 animals were orally treated with 3.0 ml/kg BW of distilled water for 60 days, while groups 3, 4, 5, 6 were similarly treated with 3.0 ml/kg BW of GFJ. Groups 4 and 7 as well as 2, 5, 6 and 8 were given 45.0 and 60.0 mg/kg BW intraperitoneal injections streptozotocin, respectively, while groups 2 and 6 animals were additionally injected with insulin (4.0 units/kg, S.C., b.d), respectively. Fasting blood glucose (FBG) and glucose tolerance tests were done. Hepatic glycogen content and glucokinase, glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK) activities were measured in homogenized liver tissues. Results Diabetic rats, groups 2 and 4–8 exhibited significantly reduced weight gain but increased polydipsia compared to controls. FBG was significantly increased in diabetic rats compared to controls but were significantly improved in GFJ-treated—compared to non-treated—diabetic rats. Similarly, diabetic rats showed significant glucose intolerance compared to controls which was improved by GFJ treatment. GFJ treatment did not improve fasting plasma insulin in diabetic rats. GFJ treatment significantly elevated glucokinase activity and hepatic glycogen concentrations but suppressed the activities of G6Pase and PEPCK, respectively, in diabetic animals. Conclusion These findings show that GFJ is not insulinotropic but improves glucose intolerance in diabetic rats by suppressing hepatic gluconeogenesis.	en_US
dc.description.sponsorship	The study was supported by a grant from the Medical Research Council of South African, and there is no conflict of interest to declare. The authors also wish to thank the Biomedical Resource Unit of the University of KwaZulu-Natal for helping with in vivo animal work as well as the final year BPharm students; Dludlu S, Govender K, Mahomed R, Moola W, Ngcobo L, Prem R, Ramasir S for helping with experimental work.	en_US
dc.identifier.citation	Hayanga JA, Ngubane SP, Murunga AN, Owira PMO. Grapefruit juice improves glucose intolerance in streptozotocin-induced diabetes by suppressing hepatic gluconeogenesis. Eur J Nutr. 2016;55(2):631-8. Epub 2015/03/21. DOI: 10.1007/s00394-015-0883-4. PubMed PMID: 25792078.	en_US
dc.identifier.issn	1436-6207
dc.identifier.journal	European journal of nutrition.	en_US
dc.identifier.uri	https://infospace.mrc.ac.za/handle/11288/595210
dc.language.iso	en	en_US
dc.publisher	Springer	en_US
dc.relation.url	https://link.springer.com/article/10.1007%2Fs00394-015-0883-4#enumeration	en_US
dc.research.unit	Grant Funded	en_US
dc.subject	Grapefruit juice	en_US
dc.subject	Diabetes	en_US
dc.subject	Insulin	en_US
dc.subject	Gluconeogenesis	en_US
dc.title	Grapefruit juice improves glucose intolerance in streptozotocin-induced diabetes by suppressing hepatic gluconeogenesis.	en_US
dc.type	Article	en_US