Pakistan Research Repository


Baig, Mukhtiar (2008) ROLE OF SERUM LEPTIN IN PRIMARY INFERTILITY IN FEMALES. PhD thesis, University of Karachi, Karachi.



Infertility is a worldwide problem which has profound social and emotional implications for the individuals concerned. According to WHO, between 8 to 12% of all couples or 50 to 80 million people worldwide experience some form of infertility during their reproductive lives. In Pakistan the ratio of primary infertility is about 4%. Infertility is defined as the failure to conceive after 1 year of regular unprotected intercourse with the same partner. The adipocyte-specific product of the OB gene, leptin, has been shown to correlate with adiposity measured either as Body Mass Index (BMI) or as percentage body fat. In the animal models, characterized by obesity and sterility as a result of the synthesis of a nonactive, truncated version of leptin, fertility has been shown to be restored by exogenous leptin treatment, suggesting that leptin is required for normal reproductive functioning. This study was designed to explore the role of serum leptin in primary infertility among females. All study subjects were grouped according to their BMI. Serum leptin was significantly correlated with BMI in all infertile and fertile groups (except in underweight fertile group), in preovulatory and luteal phase of the menstrual cycle. Significantly higher values of serum leptin were found in infertile underweight and lean subjects in preovulatory phase, while lower in overweight and obese subjects in preovulatory and luteal phase of the menstrual cycle as compared to fertile control groups in the same phase. The serum leptin levels were different in all four infertile groups as compared to respective fertile groups having similar BMI. It seems that serum leptin levels may be related in the process of fertility. Serum leptin was significantly different in all four fertile and infertile groups having different BMI but it was significantly correlated with BMI (except in underweight fertile group). It appears that relationship of serum leptin with BMI is not directly related in the process of fertility. However, it can be postulated that the relationship of serum leptin with sex steroid or its direct actions on its receptors in hypothalamus, pituitary and ovary may interfere with the process of fertility. Significant fluctuation of serum leptin was found during different phases of the menstrual cycle. Serum leptin levels were significantly higher in luteal phase as compared to preovulatory phase of the menstrual cycle in underweight and lean fertile and lean infertile subjects but it was not changed in overweight and obese subjects. It appears that BMI above normal level influences the relationship between serum leptin and menstrual cycle, and obesity results in the loss of fluctuation of serum leptin during the menstrual cycle. Serum leptin correlated with estradiol in lean, overweight and obese fertile groups and in overweight and obese infertile groups in both phases of the cycle. Correlation of serum leptin with testosterone, LH, FSH, progesterone, T3, T4, TSH, and prolactin was inconsistent. It appears that the leptin does not play a direct role in synthesis or secretion of these hormones in fertile and infertile subjects. However, an indirect link between leptin and these hormones cannot be ruled out. Females with low BMI need to improve their bodyweight by increasing consumption of calories to improve their serum leptin levels. In the same way obese women may improve their fertility through dietary and lifestyle modifications that can result in lowering of the circulating leptin concentrations. The recommendations for underweight, overweight and obese subjects with infertility are closely related to the ramification of the problem. Once the patient has been classified as underweight, overweight or obese, the weight management should be offered as a first line of treatment option because weight loss improves metabolic functions, hormonal profile and leads to marked recovery or improvement of reproductive function. Present study indicates that serum leptin play some role in the process of fertility. However, the serum leptin levels are not exclusively responsible for reproduction and numerous other factors are implicated in this complex process. Leptin may be a' metabolic signal that provides a link between adipose tissue, energy availability, and the reproductive axis. Further investigations are needed for a better understanding of the role of serum leptin in cases of primary infertility among females

Item Type:Thesis (PhD)
Uncontrolled Keywords:serum leptin, infertility, females, adipocyte, ob gene, leptin, body mass index, exogenous leptin treatment, preovulatory phase, luteal phase, menstrual cycle
Subjects:Biological & Medical Sciences (c) > Biological Sciences(c1)
ID Code:2681
Deposited By:Mr. Javed Memon
Deposited On:31 Jul 2009 12:48
Last Modified:10 Oct 2009 18:35

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