Global Journal of Health Science; Vol. 11, No. 3; 2019 ISSN 1916-9736 E-ISSN 1916-9744 Published by Canadian Center of Science and Education 83 Differences in Platelet Glycoprotein Expression During Menstruation Cycle and Ovulatory Phase Faisal M. Alzahrani 1 & Fathelrahman M. Hassan 1 1 Department of Clinical Laboratory Science, College of Applied Medical Science, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia Correspondence: Faisal M. Alzahrani, Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Imam Abdulrahman Bin Faisal University, P.O. Box: 1982, Dammam 31144, Saudi Arabia. Tel: 966-56-665-5776. E-mail: fmzahrani@iau.edu.sa Received: November 4, 2018 Accepted: February 15, 2019 Online Published: February 25, 2019 doi:10.5539/gjhs.v11n3p83 URL: https://doi.org/10.5539/gjhs.v11n3p83 Abstract Introduction: The variations in the physiological properties of female platelets during menstrual cycle phases, pregnancy and postmenopausal women to interactions with platelet CD49b, CD42b, CD41a and CD61 expression glycoprotein receptors were not well understood. Therefore, the aim of the present study was to evaluate the expression of these glycoprotein receptors during menstruation and ovulatory phase of menstrual cycle in reproductive age women. Methods: It is across section study including 44 healthy young non-hormonal contraceptives taking women aged between 19-44 years to determine the effect of estrogen on the expression level of platelet glycoprotein receptors (GPIb, GPIIa, GPIIb and GPIIIa) in its resting state in women in reproductive age. Results: No significant difference in the expression of CD42b, CD41a and CD61 between menstruation and ovulatory phases in resting platelets in all subjects. However, this study showed a significant difference in CD49b expression in none-Arab ethnic subjects compared to Arab women. Conclusion and Recommendations: This study suggested CD49b glycoprotein receptor used to be the commonly expression on the surface of platelet at some stage in menstruation and ovulatory segment of menstrual cycle in reproductive age women in turn extended platelet activity. Further studies including large number of subjects, platelet integrin gene polymorphisms and progesterone factors changes in platelet clotting associated to menstrual cycle should be conducted. Keywords: hemostasis, platelets, glycoprotein, estrogen, menstruation, ovulatory phase 1. Introduction Platelet plasma membrane supports more than 50 categories of receptors. These heterodimeric receptors support platelet adhesion and aggregation in the process of hemostasis. In case of blood vessel wall injury, platelets are recruited to the site of vascular injury where the action of glycoprotein (GP) receptors take place due to exposure of subendothelial matrix which contains ligands for these receptors that includes collagen (Kiefel et al., 1995). Platelet aggregation activity is higher in females compared with males. The association between the phase of the menstrual cycle and platelet activity appears to vary with the type of agonist, but platelet aggregation is consistently lowest in the mid-luteal phase irrespective of the agonist used (Nir et al., 2010). Several physiologic properties of platelets from women have been shown to vary with the phase of the menstrual cycle. We have found that platelets from women bound more fibrinogen during the luteal phase (defined as 14 or fewer days from the onset of the next menstrual cycle, or the second half of the menstrual cycle) than during the follicular, suggesting a hormonal regulation of glycoprotein (GP) IIb-IIIa activation (Faraday et al., 1997). The number of α2-adrenergic receptors has been shown to peak at the onset of menses and to drop to 74% to 79% of that value during the middle of the cycle. Studies (Jones et al., 1983; Tarantino et al., 1994) suggest estrogen and/or progesterone regulate platelet activation and function. Estrogen- and androgen-responsive genes (Chen & Mehta, 1996; Gopal et al., 2000). There are controversies between the differences in platelets receptors expression between menstrual cycle phases during pregnancy or with hormone replacement therapy (HRT), but the exact effects are still not well understood. In the present study; we aimed to evaluate the expression of these CD Markers: CD42b; GPIb alpha,