title: Comparative effect of Citrus sinensis and carbimazole on serum T4, T3 and TSH levels.
abstract: BACKGROUND
  There are previous independent reports on the anti-thyroid property of Citrus sinensis. This isoflavones and phenolic acid-rich natural agent is widely consumed as dietary supplement, thus the need to investigate its comparative effect with a standard anti-thyroid drug on T4, T3 and thyroid stimulating hormone (TSH) levels.
  
  
  OBJECTIVE
  To compare the effect of Citrus sinensis and carbimazole (CARB) on blood levels of thyroid hormones (T4 and T3) and TSH.
  
  
  METHODS
  Male wistar albino rats weighing 100-150 g were employed in this research. The rats were randomly assigned to four groups of seven rats per group. Group I served as control and were administered distilled water while groups II-IV were administered with 1500 mg/kg of Citrus sinensis (fresh orange juice; FOJ), 0.1 μg/g of levothyroxine (LVT) and 0.01 mg/g of CARB, respectively, per oral once daily for 28 days. The animals were sacrificed under chloroform anaesthesia and blood sample collected by cardiac puncture and processed by standard method to obtain serum. TSH, T4 and T3 were assayed with the serum using ARIA II automated radioimmunoassay instrument.
  
  
  RESULTS
  The results showed that TSH level was significantly (P < 0.05) decreased in LVT treated group compared with the FOJ group. T4 was significantly (P < 0.05) decreased in the FOJ and CARB groups compared with the control and LVT groups. LVT significantly increased T4 when compared with FOJ group. T3 was significantly (P < 0.05) decreased in the CARB group compared with the control.
  
  
  CONCLUSIONS
  These findings suggest that FOJ alters thyroid hormones metabolism to reduce their serum levels with a compensatory elevations of TSH level in a direction similar to CARB.
authors.affiliation: Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, University of Uyo, Uyo, Akwa Ibom, Nigeria.
authors.forename: Okon Akpan
authors.initials: OA
authors.lastname: Uduak
authors.affiliation: Department of Physiology, College of Medical Sciences, University of Calabar, Calabar, Cross River, Nigeria.
authors.forename: Elemi John
authors.initials: EJ
authors.lastname: Ani
authors.affiliation: Department of Obstetrics and Gunaecology, University of Uyo Teaching Hospital, Uyo, Akwa Ibom, Nigeria.
authors.forename: Emmauel Columba Inyang
authors.initials: EC
authors.lastname: Etoh
authors.affiliation: Department of Physiology, University of Port Harcourt, Port Harcourt, Rivers State, Nigeria.
authors.forename: Adienbo Ologbagno
authors.initials: AO
authors.lastname: Macstephen
keywords: Citrus sinensis; carbimazole; thyroid hormones; thyroid stimulating hormone