IBN AL- HAITHAM J. FO R PURE & APPL. SC I VO L.22 (3) 2009 Study the Effect of Rifampicin in the Level of Thyroid's Gland Ho rmones and Thyroid - Stimulating Hormone in Rabbits D. A. Sabrei De partment of Biology, College of Education Ibn AL- Haitham, University of Baghdad Abstract The aim of this st udy was intended to st udy the effect of r ifampicin in the lev el of thy roid's gland hormones (T4 ، T3) and thy roid -stimulating hormone (TSH) in rabbits. Eight male rabbits were used through out this study , their weights were measured before the starting of the exp eriment. Animals were divided into two group s (each group contains 4 rabbits), the first group was administ rated daily with 15 mg/Kg p hy siological nor mal salin e for 35 days and used as a control group , while the second group was administ rated with 15 mg /Kg d aily for 35 day of rifampicin capsule 300 mg. At the end of the exp eriment, all of animal group s were weighted and the sera was p rep ared to measure the hormones. The results showed that there was a significant de crease (P < 0.05) in the mean of animals weights in the second group that was treated with rifampicin in comp arison with the control group . A significant increase (P < 0.05)was in T4, and T3 hormones level, and a si gnificant decrease (P < 0.05)was in TSH hormone level in the second group that t reated with rifampicin in comparison with t he control group . From this study , can conclude that rifampicin has a negative effect on thy roid gland function which might disorder on the secretion activity of thy roid gland hormones. Key words: Rifampicin, Thyroid Gland, Thyroid Hormone s. Introduction The thy roid is one of the lar gest endocrine glands in the body . This gland is found in the neck inferior to (below) the thy roid cartilage (also known as Adam's app le in men) and at approximately the same level as t he cr icoid cartila ge(1). The thy roid controls how quickly the body burns energy , makes p roteins, and how sensitive the body should be to other hormones (2). The primary function of the thy roid is p roduction of the hormones thy roxine (T4), IBN AL- HAITHAM J. FO R PURE & APPL. SC I VO L.22 (3) 2009 triiodothy ronine (T3), and calcitonin. Up to 80% of the T4 is converted in to T 3 by p erip heral organs such as the liver, kidney and sp leen. T3 is about ten times more active than T4 (3). Thy roxine (T4) is sy nthesized by the follicular cells from free ty rosine and of the ty rosine residues of the protein is called thy roglobulin (TG). Iodine is cap tured with the "iodine trap" by the hy drogen p eroxide generated by the enzy me thy roid peroxidase (TPO) (4) and linked to the 3' and 5' sites of the benzene ring of the ty rosine residues on TG, and on free tyrosine. Up on st imulation by the thy roid -stimulating hormone (TSH), the follicular cells reabsorb TG and p roteolytically cleav e the iodinated ty rosines from TG, forming T4 and T3 (in T3, on e iodine is absent comp ared to T4), and releasing them into the blood. Diiodinase enzy mes convert T4 to T3 (5). Thy roid hormones that are secreted from the gland are about 90% T4 and about 10% T3. (3) Cells of the brain are a major target for the thy roid hormones T3 and T4. Thy roid hormones p lay a p articular crucial role in br ain maturation during f etal develop ment. (6) A transp ort protein (OATP1C1) has been identified that seems to be imp ortant for T4 transp ort across the blood brain barrier. A second transp ort p rotein (M CT8) is imp ortant for T3 transp ort across brain cell membranes (7). In the blood, T4 and T3 are p artially bound to thy roxine-bindin g globulin. Only a very small fraction of the circulating hormone is free (unbound) - T4 0.03% and T3 0.3%. Only the free fraction has hormon al activity (8). The p roduction of thy roxine and triiodothy ronine is regulated by thy roid -st imulating hormone (TSH), released by the anterior p ituitary (that is in turn released as a result of TRH release by the hypothalamus) (8),(9). Rifampicin, or Rifad in, or R ifampin is a semisy nthetic antibiotic derivative of rifamy cin SV. Rifamp in is a red-brown crystalline p owder very slightly soluble in water at neutral p H, freely soluble in chloroform, soluble in ethy l acetate and in methanol. Its molecular we ight is 822.95 and its chemical formu la is C43H58N4O12. The chemical name for rif amp in is either: 3-[[(4-M ethy l-1-pip eraziny l)imino]methy l]rifamy cin or 5,6,9,17,19,21-hexahy droxy -23-methoxy -2,4,12,16,20,22- heptamethy l-8-[N-(4-methy l-1-p iperaziny l)formimidoyl]-2,7-(ep oxyp entadeca [1,11,13]trienimino)nap htho[2,1-b]furan-1,11(2H)-dione 21-acetate.(10) Its structural formula is: IBN AL- HAITHAM J. FO R PURE & APPL. SC I VO L.22 (3) 2009 Rifampicin drug i.e. (rifamp in) Capsules, and (rifampin) for Injection IV an active antibiotic used for tuberculosis and against some gram negative, gr am p ositive, some enteric bacteria, and my cobacterium. Rifampicin binds strongly to DNA dep endent RNA p olymerase thus it inhibits RNA sy nthesis in bacteria and Chlamydia (11), (12). Rifampicin has many sides effects for examp le it causes anemia (13), thrombocy top enia, and leucopenia (14), also rifampicin reduces the level of glutathione, creatinine, WBCs counts and the level of lip id (15) ….etc. Few of researches insinuate that Rifampicin may increase T3 level, and until y et to our knowledge, no st udy was devoted to the st ill p oorly exp loited asp ect of the effect of Rifampicin on the level of thy roid gland hormones, i.e. does the Rifampicin h as side effects on the thy roid gland function, which is the aim of the present study . Material and Methods Eight male rabbits were used in this study were taken from the animal house in the Biotechnolo gy Researches Center / Al – Nahrain University , and their ages were between, (9 – 12) months. Isolated in a relatively controlled environ ment at a temp erature of a bout 37°C, their weights were between (1500 – 1250) gm at the beginnin g of the exp eriment ,their weights about and they were given free access for tap water and food adlibitum. Animals were div ided into t wo group s (each group contains 4 rabbits) as follows: 1. First group was administ rated daily with 15 mg / kg p hysiological normal salin e by Orogastric tube for 35 day s and used as a control group . 2. Second group was administ rated daily with 15 mg / kg of rifampicin 300 mg by Orogastric tube for 35 day s. At the end of the exp eriment the weights of the animals were taken. and p ull up the blood by heart p uncture and p rep ared the sera to measure the thy roid gland hor mones (T4, T3) and thy roid -stimulating hor mone (TSH) by the (ELISA method) and used the sp ecific ELI SA hormones kits for (T 4, T3 ), and (TSH). The exp eriment and the hormonal assay were done in IBN AL- HAITHAM J. FO R PURE & APPL. SC I VO L.22 (3) 2009 the laboratory of the Biotechnology Researches Center / Al – Nahrain Univ ersity from (20 / November / 2008) to (25 / January / 2009). Results and Discussion Animals treated with rifampicin showed a significat (P < 0.05) decrease in the body weights (from 1450.00  50.00 to 467.50 ± 46.26) gm in c omparison with the animals weights of the control group (from 1250.00  104.08 to 1825.00  85.39) gm (tab-1). These changes reflect the effect of rifampic in administration on the thyroid gland func tion i.e. increase secretion it’s hormones (T4 , T3) thus increase the body’s basal metabolic rate, stimu late carbohydrate metabolism ,break down fats, and affect protein synthesis.(2), (16),(17), (18). Also the results showed a significant increase (P < 0.05) in T4, and T3 hormone level, and a s ignificant decrease (P <0.05) in TSH hormone level in comparison w ith the control group (tab- 2). These results s how that rifampicin had side effects on thyroid gland func tion i.e. increase forming and release it s hormones over the normal value especially (T4 & T3), that’s mean primary hyperthyroidism and the weights results above proved that. May be it s increase thyroxine (T4) s ynthesized by the follicular cells from free tyrosine or from the tyrosine residues of the protein called thyroglobulin (TG) (10), (19). A decrease that happened to TSH it’s a result to the negative feed back mechanism (18),(19), i.e. thyroxine T4 and triiodothyron ine T3 is regulated by thyroid-stimulating hormone (TSH), released by the anterior pitu itary (that is in turn released as a result of TRH re lease by the hypotha lamus). The thyroid and thyrotropes form a negative feedback loop: TSH produc tion is suppressed when T4 level is high, and vice versa. The TSH produc tion itself is modulated by thyrotropin-releasing hormone (TRH), which is produc ed by the hypothalamus and secreted at an increased rate in situations such as cold (in which an accelerated metabolism would generate more heat). TSH production is blunt ed by somatostatin (SRIH), rising levels of glucocorticoids and sex hormones IBN AL- HAITHAM J. FO R PURE & APPL. SC I VO L.22 (3) 2009 (estrogen and testosterone), and excessively high blood iodide concentration (20). The results concluded that rifamp icin had negative effect on thyroid gland func tion which might have disorder on the secretion activity of thyroid gland hormones. Re ferences 1. Anonymous, (2003). The Thyriod gland. Internet address: www.umm.edu. pp: 1-2. 2. Miller, F.R. & Netterville, J.L. (1999). Med. Clin. North. Am., 83: 247-259. 3. Nussey, Stephen & Whitehead, Saffron (2001). The thyroid gland in Endocrinology: An Integrated Approach. Published by BIOS Scientific Publishers Ltd. pp: 225. 4. Ekholm, R. and Bjorkman, U. (1997). Endocrinology, 138 (7): 2871–2878. 5. Bianco, A.C.; Salvatore, D.; Gereben, B.; Berry, M.J. & Larsen, P.R. (2002).. Endocr. Rev., 23 (1): 38–89. 6. Kester, M.H.; Martinez de Mena, R.; Obregon, M.J.; Marinkovic, D.; Howatson, A.; Visser, T.J.; Hume, R. & Morreale de Escobar, G.(2004). J. Clin. Endocrinol. Metab., 89(7):3117–3128. 7.Jansen, J.; Friesema, E.C.H.; Milic i, C. & Visser, T.J. (2005). Thyroid, 15: 757-768. 8.Yalçin, B. & Ozan, H. (2006). Journal of the American College of Surgeons, 202 (2): 291–6. 9. Taurog, A. (1996). Hormone Synthesis. In: L. Braverman & R. Ut iger (eds.). Werner and Ingbar’s the thyroid gland. J.B. Lippincott-Kaven Co. Philadelphia. pp: 47-81. 10. Anonymous. (2009). Rifadin (Rifamp in) Drug Information Uses, Side Effects, Drug Interactions and Warnings at RxList2. Internet address: http://w ww.rxlist.com/rifadin- drug.htm. pp: 1-8. 11. Joshi, R. (2007).J.A.P.I., 54: 57-74 IBN AL- HAITHAM J. FO R PURE & APPL. SC I VO L.22 (3) 2009 12. Mihic, P. & Gandhi, T. (2008) .Pharmacology Reviews, 2(3):1-1. 13. M ansouthi, W. (2008).Biol. med. Central., 8 (136) :1-7. 14. M ahmood , K .(2007).Park J. Med. Sci., 23(1):1-2. 15. Adhvaryu, R.; Narsimha, R.; Minoo, H. & Bapalal, V. (2007).W. J. Gastroenterol., 13 ( 23): 3199-3205. 16. Simon, H.(2003). Hypothyroidis im. Internet address: www.thyroid.com/index./ Pp: 1-3. 17. Anony mous. (2009).Thyroid and Anti-Thyroid Drugs. Internet address: http://w ww.thyroid-info.com/drugs/armour.htm pp:4. 18. Junqueira, L.C.; Carneiro, J. & Kelly, R.O. (2002). Basic Histology. 9 th . edn., Appleton and Lang, Asimon and Schuster Company, USA. pp: 218- 230. 19. Inzucchi, S.; Burrow, G. (1999). The thyroid gland and reproduc tion In: S. Yen; R. Jaffe & R. Barbieri (eds.). Reproductive Endocrinology, Physiology Pathology and Clinical Management. 4 th . edn., W.B. Saunders Company, Philadelphia. pp: 314-318. 20. Wikipedia, the free encyclop edia. (2009). Thy roid. Internet address: Wikipedia, the free encyclopedia.htm . pp: 1 of 1. Table (1): Explain the e ffect of administration rifampicin on the Rabbits Mean weights in treated and control group M  SE: M ean  Stander Error * : Significant Difference (P <0.05) Groups M ean weight(gm) (zero time) M  SE M ean weight (gm) (end of treatment) M  SE 1. Control group 1250.00  104.08 1825.00  85.39 2.Group treated with rifampicin 1450.00  50.00 467.50  46.26 * IBN AL- HAITHAM J. FO R PURE & APPL. SC I VO L.22 (3) 2009 Table (2): Explain the e ffect of administration rifampicin in the Level of T4, T3, and TS H in Rabbits i n treated and control group M  SE: M ean  Stander Error * : Sign ificant Difference (P <0.05) Groups T4 µg / dl M  SE T3 ng / ml M  SE TSH µu / l M  SE 1.Control group 6.05  0.16 0.93  0.11 0.80 ± 0.04 2.Group treated with rifampicin 8.80  0.45 * 2.53  0.13 * 0.18  0.05 * 2009) 3( 22المجلد مجلة ابن الھیثم للعلوم الصرفة والتطبیقیة والهرمون مستوى هرمونات الغدة الدرقیةفي الریفامبیسین ردراسة تأثیر عقا في األرانب ةالمحفز للدرقی دالیا عبد اللطیف صبري ابن الهیثم،جامعة بغداد -قسم علوم الحیاة ، كلیة التربیة الخالصة والهرمون T4 (T3,(مستوى هرمونات الغدة الدرقیة في الریفامبیسین رتأثیر عقا دراسة الى هدفت الدراسة الحالیة أوزانها ومن ثم قسمت على تخذأ اذ أرانب ذكور 8الدراسة في هذه استخدم .األرانبفي (TSH)ةالمحفز للدرقی ملحي الفسیولوجي )مجموعة سیطرة( األولىالمجموعة جرعت .أرانب 4مجموعتین كل مجموعة مكونة من بالمحلول ال normal saالسوي line p hy siological ة وجرعتیومًا ، 35مدة و كغم / ملیغرام 15 یومیا بجرعة المجموعة الثانی . یوماً 35مدة و یومیًا كغم / ملیغرام 15 مقدارهاوبجرعة ملیغرام 300 الریفامبیسین عقارب (TSH). و T4 (T3,(وزنت الحیوانات وتم سحب الدم لتهیئة األمصال لقیاس مستوى هرمون في نهایة المعاملة p)وجود نقصان معنوي النتائج وأظهرت في معدل أوزان الحیوانات المعاملة بالریفامبیسین مقارنًة بمجموعة (0.05> p)السیطرة وحصول زیادة معنویة p)ونقصان معنوي T3و T4,في مستوى هرموني (0.05> في مستوى هرمون (0.05> TSH مقارنًة بمجموعة السیطرة . فعالیة الغدة الدرقیة اإلفرازیة مما یؤدي الى حدوث خلل في الریفامبیسین تأثیرًا سلبیًا فيلعقار نستنتج من هذه الدراسة إن . اإلفراز الهرموني .ریفامبیسین، الغدة الدرقیة، هرمونات الغدة الدرقیة: كلمات المفتاح