oxytocin and Amenorrhea

Recent data demonstrate the anabolic effect of oxytocin on bone. Bone cells express oxytocin receptors. Oxytocin promotes osteoblasts differentiation and function, leading to an increased bone formation with no effect on bone resorption and an improvement of bone microarchitecture. Oxytocin is synthetized by osteoblasts, and this synthesis is stimulated by estrogen. Animal studies demonstrate a direct action of oxytocin on bone, as the systemic administration of oxytocin prevents and reverses the bone loss induced by estrogen deficiency. Although oxytocin is involved in bone formation in both sexes during development, oxytocin treatment has no effect on male osteoporosis, underlining the importance of estrogen that amplifies its local autocrine and paracrine secretion. There are few human data showing a decrease in the oxytocin serum level in anorexia nervosa independently of estrogen and in amenorrheic women associated with impaired bone microarchitecture; in post-menopausal women a higher oxytocin serum level is associated with higher bone density, but not in osteoporotic men. Oxytocin displays many effects that may be beneficial in the management of osteoporosis, cardiovascular diseases, cognitive disorders, breast cancer, diabetes and body fat gain, all age-related diseases affecting elderly women, opening exciting therapeutic perspectives, although the issue is to find a single route, dosage and schedule able to reach all these targets.

Topics: Amenorrhea; Animals; Anorexia Nervosa; Autocrine Communication; Bone and Bones; Bone Density; Breast Neoplasms; Cardiovascular Diseases; Cognitive Dysfunction; Diabetes Mellitus; Estrogens; Female; Humans; Male; Osteoporosis, Postmenopausal; Oxytocin; Paracrine Communication; Sex Characteristics

Topics: Amenorrhea; Breast Feeding; Cesarean Section; Colitis; Diet; Female; Humans; Immunity, Maternally-Acquired; Infant Care; Infant, Newborn; Infant, Newborn, Diseases; Jaundice, Neonatal; Lactation; Mastitis; Milk, Human; Nutritive Value; Obesity; Oxytocin; Postpartum Period; Pregnancy; Prolactin

This postpartum period is characterized by stimulation of lactation and suppression of ovulation. During pregnancy a number of hormonal changes prepare the breasts for lactation following delivery. The process of lactation is functionally related to the suppression of ovulation. These two physiologic changes observed in the puerperium are considered in detail in this review.

Topics: Amenorrhea; Animals; Female; Follicle Stimulating Hormone; Humans; Hypothalamo-Hypophyseal System; Lactation; Luteinizing Hormone; Ovary; Oxytocin; Periodicity; Postpartum Period; Pregnancy; Prolactin; Sleep

Topics: Adrenocorticotropic Hormone; Amenorrhea; Animals; Breast; Bromocriptine; Estrogens; Female; Galactorrhea; Hormones; Humans; Lactation; Lactation Disorders; Milk; Milk, Human; Oxytocin; Pregnancy; Progesterone; Prolactin; Testosterone

Against the background of renewed interest in the existence of reflex ovulation in many animal species and the possibility of its existence in man, this review on current research efforts embraces the multitude of nervous influences and stimuli accompanying cohabitation. Species showing reflex ovulation are not restricted to those using this as the sole ovulatory mechanism, but include also so-called facultative ovulators, which seem to use this mechanism as a last resort to assure reproductive capacity under adverse situations (rat); and species which for the length of the standing heat period become temporarily induced ovulators for the optimal coordination of all necessary steps to assure fertility (cattle, pig, sheep); and species in which frequent cohabitation (rat) or a single coitus after artificial insemination (sheep) assures either optimal ovulation or conception rates. Copulation might not always be essential; some of the cohabitation-related reflexes might be transmitted by olfactory, ocular, tactile and acoustic stimuli; emotions may play a role. These stimuli are transmitted to the CNS from the periphery by afferent nervous pathways, and are translated in the thalamic-hypothalamic-pituitary complex into neurohormonal phenomena, causing ovulation; or may cause, mainly by LH and/or oxytocin discharge, an acceleration or augmentation of processes involved in spontaneous ovulation. Intensive biochemical and pharmacological studies have unveiled some of the neurohormonal mechanisms involved in the hypothalamus and how these stimuli are transmitted to the pituitary or received at the ovarian level, as hormonal or neurohormonal phenomena.

Topics: Amenorrhea; Animals; Cattle; Coitus; Contraceptives, Oral; Cricetinae; Estrus; Female; Follicle Stimulating Hormone; Haplorhini; Horses; Humans; Hypothalamo-Hypophyseal System; Insemination, Artificial; Luteinizing Hormone; Muscle, Smooth; Ovarian Follicle; Ovary; Ovulation; Oxytocin; Pregnancy; Progesterone; Prostaglandins E; Prostaglandins F; Rabbits; Rape; Rats; Sheep; Stress, Psychological; Swine; Vagina

More than 40years ago, the endogenous opioids were first described. Their role as important neuromodulators of pain and their influence on a variety of neuroendocrine control systems within the central nervous system has been recognized. More recently, endogenous opioids and their receptor have been identified in a variety of reproductive and non-reproductive tissues outside the central nervous system. What role the opioid system plays in these peripheral tissues and organs is not completely understood and thus the subjects of current research. In the central nervous system, endogenous opioids inhibit pulsatile Gonadotropin Releasing Hormone (GnRH) release, affecting the release of gonadotropins from the pituitary, and thus mediating stress response within the central nervous-pituitary-gonadal axes in both women and men-Peripherally, endogenous opioids have been demonstrated to be present-among other organs-in the pancreas and in the ovary, where they are produced by granulosa cells and may influence oocyte maturation. In men, endogenous opioids play a role in sperm production within the testis. Opioid antagonists such as naltrexone have been used to restore cyclicity in women through improvement in insulin resistance, GnRH-pulsatility and hyperandrogenemia stemming from specific pathophysiological conditions such as hypothalamic amenorrhea, polycystic ovarian syndrome, hyperinsulinemia, ovarian hyperstimulation syndrome. Opioid antagonists have also been used to treat male sexual disorders and male infertility. In summary, endogenous opioids exert a variety of actions within the reproductive system which are reviewed in this chapter.

Topics: Amenorrhea; Analgesics, Opioid; Animals; Endorphins; Female; Humans; Hypothalamic Diseases; Male; Opioid Peptides; Oxytocin; Polycystic Ovary Syndrome; Pregnancy; Prolactin; Receptors, Opioid; Reproduction

Oxytocin has been implicated in the modulation of energy metabolism in animals. Oxytocin knockout mice develop obesity without a change in food intake, suggesting that a lack of oxytocin may reduce metabolic rate. Furthermore, administration of oxytocin centrally reduces food intake in rats, an effect reversed by an oxytocin antagonist, implying that oxytocin may regulate appetite and energy intake. We have previously demonstrated that young female athletes (in a higher energy expenditure state than nonathletes) have low nocturnal oxytocin compared with nonathletes. Whether oxytocin is associated with measures of energy homeostasis in athletes is unknown.. We hypothesized that oxytocin, a signal for energy availability, would be associated with other measures of energy homeostasis in young female athletes.. We performed a cross-sectional study of 45 females, aged 14-21 years [15 amenorrheic athletes (AA), 15 eumenorrheic athletes, and 15 nonathletes] of comparable body mass index.. Dual x-ray absorptiometry was performed to assess body composition. Indirect calorimetry was used to measure resting energy expenditure (REE). Fasting levels of oxytocin, energy homeostasis hormones irisin and fibroblast growth factor-21, and appetite-regulating hormone peptide YY were obtained.. In AA, oxytocin secretion was positively correlated with surrogate measures of energy availability, including weight (r = 0.65, P = .009) and body mass index (r = 0.61, P = .016). Furthermore, oxytocin was associated with REE (r = 0.80, P = .0003), independent of lean mass, and with irisin (r = 0.74, P = .002) and fibroblast growth factor-21 (r = 0.58, P = .024). In eumenorrheic athletes, oxytocin was associated with REE (r = 0.59, P = .021), independent of lean mass. In nonathletes, oxytocin secretion was not significantly associated with measures of energy homeostasis.. In AA, oxytocin secretion is associated with measures of energy availability and expenditure, suggesting that oxytocin may be involved in regulation of energy balance in energy deficient states. Further studies determining the role of oxytocin in appetite and energy homeostasis in athletes are warranted.

Topics: Adolescent; Amenorrhea; Athletes; Body Mass Index; Body Weight; Calorimetry, Indirect; Cross-Sectional Studies; Energy Metabolism; Female; Fibroblast Growth Factors; Fibronectins; Humans; Oxytocin; Young Adult

Preclinical data indicate that oxytocin, a hormone produced in the hypothalamus and secreted into the peripheral circulation, is anabolic to bone. Oxytocin knockout mice have severe osteoporosis, and administration of oxytocin improves bone microarchitecture in these mice. Data suggest that exercise may modify oxytocin secretion, but this has not been studied in athletes in relation to bone. We therefore investigated oxytocin secretion and its association with bone microarchitecture and strength in young female athletes.. Cross-sectional study of 45 females, 14-21 years (15 amenorrheic athletes (AA), 15 eumenorrheic athletes (EA), and 15 nonathletes (NA)), of comparable bone age and BMI.. We used high-resolution peripheral quantitative CT to assess bone microarchitecture and finite element analysis to estimate bone strength at the weight-bearing distal tibia and non-weight-bearing ultradistal radius. Serum samples were obtained every 60  min, 2300-0700  h, and pooled for an integrated measure of nocturnal oxytocin secretion. Midnight and 0700  h samples were used to assess diurnal variation of oxytocin.. Nocturnal oxytocin levels were lower in AA and EA than in NA. After controlling for estradiol, the difference in nocturnal oxytocin between AA and NA remained significant. Midnight and 0700  h oxytocin levels did not differ between groups. At the tibia and radius, AA had impaired microarchitecture compared with NA. In AA, nocturnal oxytocin correlated strongly with trabecular and cortical microarchitecture, particularly at the non-weight-bearing radius. In regression models that include known predictors of microarchitecture in AA, oxytocin accounted for a substantial portion of the variability in microarchitectural and strength parameters.. Nocturnal oxytocin secretion is low in AA compared with NA and associated with site-dependent microarchitectural parameters. Oxytocin may contribute to hypoestrogenemic bone loss in AA.

Topics: Adolescent; Adult; Amenorrhea; Athletes; Body Mass Index; Bone and Bones; Bone Resorption; Circadian Rhythm; Cross-Sectional Studies; Exercise; Female; Finite Element Analysis; Humans; Hypothalamus; Mechanical Phenomena; Oxytocin; Radius; Tibia; Weight-Bearing; Young Adult

Activation of the hypothalamus-pituitary-adrenal (HPA) axis is suggested to play a role in the stress-related inhibition of LH secretion. The aim of our study was to investigate the effects of vasopressin and oxytocin, which are increased in pituitary portal plasma in response to stress, and of glucocorticoids, the final product of HPA activation during stress, on basal plasma LH levels and on pituitary LH response to the GnRH test in amenorrheic (n = 33) and fertile (n = 13) women. Plasma LH levels were evaluated by radioimmunoassay in 2 different experimental conditions: 1. Basal secretion; 2. The GnRH test (10 micrograms + 10 micrograms after a 120-minute interval). These 2 evaluations were done in the presence of both placebo and a pharmacological dose of desmopressin (an analogue of vasopressin) (16.6 ngr/minute), oxytocin (0.2 ngr/minute) or hydrocortisone (4.1 mg/minute). None of these drugs modified basal plasma LH levels either in amenorrheic patients or in controls. Hydrocortisone inhibited the GnRH-induced LH increase in amenorrheic women. These data suggest that the glucocorticoids might play a role in LH secretion and indicate a possible participation of the HPA axis in the impairment of the hypothalamus-pituitary-gonadal axis in women with psychogenic amenorrhea.

Topics: Adult; Amenorrhea; Deamino Arginine Vasopressin; Female; Humans; Hydrocortisone; Hypothalamo-Hypophyseal System; Luteinizing Hormone; Oxytocin; Pituitary-Adrenal System; Radioimmunoassay; Stress, Physiological

Eighteen cases of advanced extra-uterine pregnancy are reported. The difficulty of diagnosis is discussed; the only symptoms of any help were amenorrhoea, lower abdominal pain, postmaturity and failed induction of labour. The physical findings were variable and none were absolutely reliable. In 17 cases the fetus was dead on admission and early laparotomy was performed, and in 17 patients it was possible to remove the placenta completely.

Topics: Adult; Amenorrhea; Female; Humans; Labor, Induced; Middle Aged; Oxytocin; Palpation; Placenta; Pregnancy; Pregnancy, Ectopic; Pregnancy, Prolonged; Radiography; Time Factors

Topics: Abortion, Induced; Adult; Amenorrhea; Biopsy; Blood Flow Velocity; Cervix Uteri; Depression, Chemical; Endometrium; Estriol; Female; Humans; Hydrogen; Labor, Obstetric; Middle Aged; Oxytocin; Pregnancy; Regional Blood Flow; Time Factors; Uterus

Topics: Amenorrhea; Female; Gonadotropins, Pituitary; Humans; Oxytocin; Pituitary Gland