Effects of tramadol abuse on plasma concentration of leptin and agouti related protein (AgRP)

Abstract

The current study is a trial to understand the effect of one of the most commonly used analgesics and also one of the most abused drugs “tramadol” on the hormones regulating the appetite and subsequently the body weight “Leptin and AgRP”. This study included 40 participants, classified into four groups, 10 participants each. Group I (GI) and group II (GII) composed of control healthy volunteer males having confirmed negative tramadol and des-methy-tramadol in their blood. GI participants aged 38.67 ± 2.35 years and have normal weight with Body Mass Index (BMI) equal 21.9 ± 0.67. GII participants aged 37.40 ± 2.67 years and having BMI equal 33.93 ± 0.57. Group III (GIII) and group IV (GIV) had positive tramadol and des-methyl- tramadol in their blood confirmed by gas chromatography-mass spectrometry. GIII participants have normal weight with BMI equal 22.55 ± 0.88 and age equal 37.66 ± 2.30 years. GIV participants were obese with BMI equal 33.83 ± 0.81 and age equal to 36.40 ± 2.60 years. All subjects with hypertension and diabetes mellitus were excluded. Human leptin hormone was measured depending on immunoradiometric assay IRMA; the human AgRP hormone was measured by using a quantitative sandwich enzyme immunoassay technique. Leptin concentration in obese non tramadol users (GII) is increased (14.78 ± 0.74) in comparison to the normal weight non tramadol users (GI) (6.96 ± 0.43) but it is lower than the obese tramadol users (GIV) (17.68 ± 0.6) while the normal weight tramadol users (GIII) showed increased leptin concentration (14.02 ± 0.83) in comparison to the normal weight non tramadol users (GI) (6.96 ± 0.43) and decreased leptin concentration in comparison to the obese tramadol users (GIV) (17.68 ± 0.6). Regarding the blood concentration of AgR P, it was higher in GII (17.12 ± 1.14) than GIV (11.85 ± 0.79) and lower in GIII (17.33 ± 0.98) than GI (25.05 ± 0.72). So it can be concluded that using tramadol was associated with an increase in leptin concentration either on comparing the normal weight groups or the high BMI groups. An opposite effect was seen on AgRP concentration. There is positive correlation between leptin and BMI in the control groups (GI and GII) and negative correlations in the tramadol users in groups (GIII and GIV) meanwhile there was a negative correlation between AgRP and BMI in the control groups (GI and GII) and positive correlations in the tramadol users in groups (GIII and GIV). A negative correlation between leptin and AgRP in all the studied groups. It is concluded that tramadol abuses increased leptin concentration in both normal weight and obese cases in comparison to non-abusers either normal weight or obese. Meanwhile, it decreased AgRP concentration in both normal weight and obese cases in comparison to non-abusers either normal weight or obese. Also, the review of the literature concluded that they are also altered in different cases of drug abuse so it is recommended to study the effect of other abused drugs on these hormones.