The Role of Oxytocin, Prolactin, and Estrogen in Male Sexual Functions
Authors: Elsayed Azab Azab 
Published: March 2022

Background: The dysfunction in sexual ability has effects on the quality of life in men. Oxytocin plays a role in sexual and social behaviors. Hyperprolactemic males had erectile dysfunction. Endogenous estrogens in men, are not only important for health integrity but can additionally cause the promotion of many diseases. Objectives: The current review aimed to high light on the role of oxytocin, prolactin, and estrogen in male sexual functions. Oxytocin neurons have been heavily implicated in mediating sexual behavior in both humans and animals. Oxytocin hormone regulates social behaviors such as mating, maternal/paternal care, and bonding. Oxytocin levels rise during mating in females and males in humans and animals and may mediate anxiolytic/calming effects of sexual activity and antidepressant effects.Oxytocin’s role in regulating erection and ejaculation has been studied in mice and rats. Oxytocinergic projections from the paraventricular nucleus to the hippocampus, medulla oblongata, and spinal cord facilitate penile erection. Prolactin (PRL) serves a dual function both as a circulatory hormone and as a cytokine. PRL is known to be involved in the control of male copulatory behavior in humans, mice, rats, and other rodent models. It release during copulation in males and has a positive modulation for various aspects of testicular functions which hinting at the crucial role of prolactin in male reproduction. The lower concentration of prolactin was associated with reduced seminal vesicle volume and ejaculate in the infertile human male. Hypoprolactinemia has been associated with premature ejaculation and erectile dysfunction. Hyperprolactinemia can be caused by tumors, drugs, or idiopathic, leading to alterations in sexual behavior as loss of libido and erectile dysfunction. It is also reported that it can cause endocrine disturbances leading to abnormal levels of testosterone, FSH, and LH. Chronic hyperprolactinaemia suppresses copulatory behaviour in animal models and yields sexual dysfunction and other side effects in men. In men, testosterone acting via its action on androgen receptors may be dependent on the action of aromatase enzyme on of testosterone and converting it to estradiol (E2). Estrogens act through ERα and ERβ at the plasma membrane and in the nucleus to regulate functions of many organs in men. The role of estradiol action on libido is seen at various levels of regulation, starting with direct effects in the brain. Not only does estradiol modulate sexual behavior in the adult male, it also appears to organize the early brain to program sexual behavior. The exact role of estradiol in each area of male sexual function including libido, spermatogenesis, and erectile function is difficult to determine. A complex balance of testosterone, estradiol, aromatase, and estrogen receptors in brain, testes, and penis, confirmed the indispensable and highly regulated hormonal interaction of estrogen in the male. Conclusion: It can be concluded that oxytocin hormone regulates social behaviors such as mating, maternal/paternal care, and bonding. PRL is involved in the control of male copulatory behavior in humans, rats, mice, and other rodent models. Hypoprolactinemia has been associated with reduced seminal vesicle volume, premature ejaculation, and erectile dysfunction. Hyperprolactinemia can be caused by tumors, drugs, or idiopathic, leading to alterations in sexual behavior as loss of libido and erectile dysfunction. Also, hyperprolactemic males had erectile dysfunction. Estradiol modulates sexual behavior in the adult male, and appears to organize the early brain to program sexual behavior.