The present descriptive study was designed to compare thyroid hormones (Triiodothyronin T3 and Thyroxin T4), testosterone hormone levels and haematological parameters in obese rats which treated with green tea (GT) or L-Carnitine (LC) and normal rats. Forty male rats were randomly assigned into four groups, first group (10 normal rats as control (-ve)), second group (10 obese rats as positive control (+ve)), third group (10 obese rats for treatment with green tea aqueous extract) and fourth group (10 obese rats for treatment with L-Carnitine). Our goal is to achieve obesity model in 8 weeks followed by treatment period for 9 weeks daily with both 10% aqueous extract of green tea and 21 mg L-Carnitine/kg body weight. T3 and T4 were decreased in third group which treated with green tea aqueous extract on contrast animals in fourth and second groups which treated with L-Carnitine and control positive respectively were increased compared with control group. Treatment of obese male rats with green tea aqueous extract caused decrease in red blood cells (RBC’s) and blood haemoglobin and increase in both white blood cells (WBC’s) and haematocrit % (PCV%) ,while L-Carnitine caused increase in levels of blood haemoglobin (Hb), red blood cells (RBC’s), white blood cells (WBC’s) and haematocrit % (PCV%) compared with control and positive control , while haematocrit (PCV%) in rats positive control group was decreased compared with control and all treatment groups. Green tea extract and L-Carnitine had significant decrease on body weight gain, secretion of testosterone hormone in obese rats, as well as T3 and T4. They were decreased with green tea treatment while were increased with L-Carnitine treatment. L-Carnitine cause increase in hematological parameters such as RBC’s, WBC’s, PCV% haemoglobin concentration (Hb), but RBC’s and haemoglobin concentration (Hb) were decreased with green tea treatment compared with control and control positive.
Obesity has reached pandemic proportions around the world and now poses one of the greatest public health challenges. One billion of the approximately 6.5 billion people in the world are estimated to be overweight body mass index (BMI);25kg /m2 and of these at least 300 million are obese (BMI);30kg /m2 (WHO, 2009). These numbers are predicted to more than double to reach 2.3 billion overweight and 700 millions obese by 2015 (WHO, 2010). Rats injected with pure green tea intra-pretonialy were studied for acute effects on endocrine systems. significantly reduction in food intake, body weight gain, blood levels of testosterone, as well as growth of the prostate, uterus, and ovary were observed in lean and obese male Zucker rats, YUNG, et al., (2000). Green tea extract at dose level 5.0g% has the potential to alter the thyroid gland physiology and architecture, that is, enlargement of thyroid gland as well as hypertrophy and/or hyperplasia of the thyroid follicles and significant decrease in serum T3 and T4, and a parallel increase in serum thyroid stimulating hormone (TSH), Chandra et al. (2010). Dietary supplementation of L-Carnitine has no effect on serum levels of estrogen, progesterone and testosterone in cats following ovariohysterectomy. Yet, long-term study is recommended, Tavakoli et al., (2017). L-Carnitine is a peripheral antagonist of thyroid hormone action at least in some tissues. L-Carnitine was able to both reverse and prevent/minimize nine hyperthyroidism related symptoms, Salvatore et al., (2001). Triiodothyronin (T3) and Thyroxin (T4) were increased in obese rats treated with L-Carnitine, Ridha ; Kocher (2015). This work, was undertaken to evaluate the serum testosterone hormone, thyroid hormones (T3 ;T4) and blood picture effects of Green tea and L-Carnitine supplementation in male obese rats were treated by using L-Carnitine supplementation and aqueous extract of green tea .
Reduction of body weight % in obese rats treated with (GT ; LC):
Depicts the progression of body weight percentage in the four groups of animals. Effect of aqueous water extract prepared from green tea and L-Carnitine on body weight gain % of obese rats presented in Table (2). The mean of body weight gain % of the positive control group increased as compared to the negative control group (74.1% and 72.3%), respectively. the progression of body weight % of two treated groups with green tea aqueous extracts and treated group treated with L-Carnitine showed decreased in the progression of body weight % compared with positive and negative control groups (74.1 % and 72.3%) respectively. While the progression of body weight % in group which treated with L-Carnitine (53.2%)was more decreased which treated with green tea extract (61.3%) (Table 2).Table (2): Percentage of body weight (BW) gain of male albino rats administrated with
Green Tea extract (GT) and L-Carnitine (LC) with high fat diet (HFD) for 9 weeks.
9th 8th 7th 6th 5th 4th 3rd 2nd 1st Week
72.3 69.6 63.4 57.1 46.8 38.1 27.5 17.9 11.6 G1 Control (-)
74.1 72.8 65.8 59.8 53.4 42.7 30.9 20.8 14.3 G2 Control (+)
61.3 59.8 56.9 54.3 49.6 40.1 29.7 20.3 14.2 G3 GT Treatment
53.2 50.1 45.9 39.9 36.4 30.4 21.8 12.9 10.05 G4 LC Treatment
Effects of GT ; LC on testosterone hormones levels
Rats treated with (GT ; LC) had significant decreases in testosterone hormone level. After 9 weeks of treatments were (1.08 ;1.47 ng/l) respectively compared with negative ; positive control were (3.13 ; 2.32 ng/l) respectively Table (3).
Effects of GT and LC on thyroid hormones levels
Rats treated with GT and LC had significant changes in thyroid hormones T3 and T4 levels. After 9 weeks of treatments Triiodothyronin (T3) were 46.64 and 73.00 ng/l in rats treated with GT and LC, respectively, compared with each of control positive or negative which were 77.17 and 57.03 ng/l, respectively. Thyroxin hormone (T4) were 3.58 and 4.87 µg/dl, respectively, compared with each of control positive or negative, which were 6.25 and 4.37 µg/dl, respectively. Rats which treated with GT revealed that Triiodothyronin and Thyroxine (T3 and T4), were decreased compared with each of negative or positive control, while rats which treated with LC showed that Triiodothyronin (T4) and Thyroxine (T3) were increased compared with control negative, on contrast they were decreased compared with control positive (Table 3).
Table (3): Effect of GT (aqueous extract) and L- Carnitine on serum Testosterone, T3 and T4 in male albino rats.
T4 µg/dl T3 ng/l Testosterone ng/l Groups of treatments
4.37 57.03 3.13 Control negative
6.25* 77.17* 2.32* Control positive
3.58* 46.64* 1.08* Green tea treatment
4.87* 73.00* 1.47* L-Carnitine
Values are expressed as means ± standard errors, (Duncan’s multiple range test, p < 0.05).
Effect of GT extract and LC treatments on Haematological parameters:
RBC’s, WBC’s, Hb, and PCV% values increased after green tea and L-Carnitine treatments; 6.948×106, 8.87×103, 19.02 g/dl and 40.9%, respectively, and all parameters increased after treatment with green tea which were (WBC’s 8.02×103, PCV% 42.3%), on contrast the value of RBC’s is 4.778×106 and Hb content 16.4 g/dl, were decreased respectively, compared with either their negative or positive control values (Table 4).
Table (4): Effect of GT aqueous and L-Carnitine on blood picture of male albino rats.Treatments RBC’S Count WBC’S Count HB concentration HCT value
X(10) 6 ML % of Control X(10) 3 ML % of Control g/dl % of Control % % of Control
Control (-) 4.978±0.098 100.00 7.35±0.367 100.00 17.3±0.6 100.00 41.8±1.41 100.00
Control (+) 5.325±0.3 106.97 7.98±.186 108.57 18.02±0.3 104.16 41.9±2.3 100.20
Green tea 4.778±0.44 95.98 8.02±0.768 109.00 16.4±0.37 94.80 42.3±1.3 101.12
L-Carnitin6.948±0.29 139.57 8.87±0.126 120.68 19.02±0.9 109.94 43.3±0.89 103.59
All values = mean ± SE, Control (with normal diet) values are referred to 100%.
Green tea is containing polyphenols and flavonoid. In common with synthetic antioxidants, several flavonoids can interfere with thyroid hormone biosynthesis (free radical iodination) (Ferreira et al., 2002; Doerge and Sheehan 2002). Most studies of polyphenols aimed to determine the protective effects of polyphenols against diseases or toxic drugs, and relatively few investigators have examined their possible toxicity. No acute toxicity was observed after oral administration of green tea aqueous extract .The present study describes that green tea aqueous extract (GT) and L-Carnitine (LC) exposure at the high dose with (10% GT) and recommended dose of (21 mg LC/ kg body weight) as used in our investigation had reduced the gain in body weight in adult obese male albino rats in both treatments (GT and LC) compared with both control groups (+ve and -ve ) even though the average daily food intake did not differ between the groups during study period. These findings are in line with previous work, which showed that green tea and Carnitine have potential role in body weight control. But decrease in percentage of body weight (B.W) gain of male albino rats which administrated GT was less than decrease in percentage of body weight gain of male albino rats which administrated LC. The increase in weight loss in L-Carnitine-treated animals may be higher than the weight loss in fat animals treated with green tea. This is explained by the resulting increase in thyroid hormone secretion in the case of L-Carnitine treatment than in case of green tea treatment, which increases the rate of body fat metabolism. In addition, LC decreased of body weight in obese rats, because it is increase mitochondrial ?-oxidation of fatty acids. L-Carnitine supplementation increase fat mobilization from adipose tissue, while (GT and LC) have different effects on modulation of endocrine system in rats. The circulating levels of testosterone were lowered, GT at the high level intake may have anti-androgenic effects, thus influencing male fertility. Peripheral thyroid hormones (T3 and T4) are moderately increased in obese animals in control positive group. When rats were administered with (GT or LC) and weight reduction leads to a long term (9 weeks) decrease in the peripheral thyroid hormones. Triiodothyronin & Thyroxin (T3 and T4) in serum levels (Doerge and Chang 2002; Benvenga et al., 2004; El Mgeed et al 2009 and Chandra and Neela 2014). LC is a peripheral antagonist of thyroid hormone action. In particular L-Carnitine inhibits both T3 and T4 entry into the cell, so leading to their accumulation in the blood. Also Elgazzar et al., (2012), mentioned that L-Carnitine was acting thyroid hormone target tissue, and not at the level of thyroid gland as an inhibitor of thyroid hormone synthesis. Treatment with GT reduced RBC’S count and Haemoglobin content. Green tea is containing polyphenols may also have anti-nutritional effects. The inhibition of non haem absorption attributable to simultaneous tea consumption is well known; high consumption of polyphenols may increase the risk of iron depletion in populations of individuals with marginal iron status (Temme and Van Hoydonck 2002; Frank, 2016). It is important to consider that green tea, black tea, wine and coffee contain many polyphenols may be dangerous to human health, especially causing anemia.