Oestrogen increases haematopoietic stem-cell self-renewal in females and during pregnancy

In most tissues, the prevailing view is that stem cell (SC) niches are generated by signals from within the nearby tissue environment. Here, we define genetic changes altered in hair follicle (HF) SCs in mice treated with a potent SC activator, cyclosporine A (CSA), which inhibits the phosphatase calcineurin (CN) and the activity of the transcription factor nuclear factor of activated T cells c1 (Nfatc1). We show that CN/Nfatc1 regulates expression of prolactin receptor (Prlr) and that canonical activation of Prlr and its downstream signaling via Jak/Stat5 drives quiescence of HF SCs during pregnancy and lactation, when serum prolactin (Prl) levels are highly elevated. Using Prl injections and genetic/pharmacological loss-of-function experiments in mice, we show that Prl signaling stalls follicular SC activation through its activity in the skin epithelium. Our findings define a unique CN-Nfatc1-PrlrStat5 molecular circuitry that promotes persistent SC quiescence in the skin.

The incidence of many cancer types is significantly higher in the male than female populations, with associated differences in survival. Occupational and/or behavioral factors are well known underlying determinants. However, cellular/molecular differences between the two sexes are also likely to be important. We are focusing here on the complex interplay that sexual hormones and sex chromosomes can have in intrinsic control of cancer initiating cell populations, tumor microenvironment and systemic determinants of cancer development like the immune system and metabolism. A better appreciation of these differences between the two sexes could be of substantial value for cancer prevention as well as treatment.3 Introduction (Epidemiology)

In females, the reproductive age is characterized by the onset of menstruation called menarche and ceases with the onset of menopause. The female reproductive cycles are controlled by various hormones and these hormones are known as female hormonal system. The female sexual cycle is the cycle of natural changes that occurs in the uterus and ovary as an essential part of making sexual reproduction possible. Its timing is governed by endogenous biological cycles. During the first few days of each monthly female sexual cycle, the concentrations of both FSH and LH secreted by the anterior pituitary gland increase slightly to moderately, with the increase in FSH slightly greater than that of LH and preceding it by a few days. These hormones, especially FSH, cause accelerated growth of 6 to 12 primary follicles each month. Menstruation is the principal cause of iron loss in women. The menstrual period is associated to the rupture of blood vessels which irrigate the superficial layer of the endometrium. Platelets constitute the first haemostatic component that mobilizes in order to interrupt the bleeding as vascular injury occurs. During menstruation, tremendous numbers of leukocytes are released along with the necrotic materials and blood. This is probable as a result of some substances released by the endometrial necrosis which causes the outflow of leukocytes during menstruation. The paper reviewed haematological profile menstruating women,premenopause women and menopause women.