Prolactin immune system

D5 has slightly different properties than D4, and it does not have any estrogenic activity [289]. It does, however, also have adverse effects on the reproductive system, much like D4, but also on the adipose tissue, bile production, and even immune system due to D5 s effect of reducing the prolactin levels [291]. In addition, it was determined that D5 causes a significant increase in uterine tumors in rats after a 160 ppm exposure. However, it is proposed that the tumors occur in rats through a mechanism that would not affect humans [291]. D5 also acts as a dopamine agonist and it can cause adverse effects on the nervous system in humans [291]. For exposures to D6 in rats, an increase in liver and thyroid mass and reproductive effects were observed [292]. 

TCDD on the immune system." One potentially important indirect mechanism operates through effects on the endocrine system. Glucocorticoids, sex steroids, T4, growth hormone, and prolactin have been shown to regulate immune responses, and 2,3,7,8-TCDD has been shown to alter the activity of all of them (see also sections on endocrine and reproductive effects). 

Prolactin appears to play a role in regulating the immune system in mammals, though the significance of this is not yet clear. Receptors for the hormone have been... 

There were several relatively early reports that prolactin can have actions on cells and tissues of the immune system. More recently a variety of effects of the hormone on lymphocyte-related cells have been described and investigated in some detail. 

A variety of effects of prolactin has been described on normal tissues and cells of the immune system, deriving from rats, mice and humans [21,22], The nature of the effects varies they can be either stimulatory or inhibitory, depending on the system studied and the concentration of prolactin. Thus, in the rat, hypophysectomy leads to impairment of the immune response which can be restored by injection of prolactin [118]. On the other hand, excessively high levels of prolactin can also give rise to an impaired immune response. 

Prolactin. A versatile hormone that is involved in the regulation of proliferation and differentiation of a variety of cells in the immune system. May play a role in the pathogenesis and clinical expression of autoimmune diseases (e.g. systemic lupus erythematosus). 

Amino acid sequence of human prolactin B. Shome, A. F. Parlow, J. Clin. EndocrinoL Metab. 45, 1112 (1977). Effects of prolactin on the murine immune system E. Nagy et al, Acta EadocrinoL 102, 351 (1983). Symposium on clinical endocrinology Horm. Rex 22, 129-252 (1985). General... 

Wu, H., Devi, R. and Malarkey, W.B. (1996) Expression and localization of prolactin messenger ribonucleic acid in the human immune system. Endocrinology, 137, 349-353. 

Such events show how the immune, endocrine and central nervous systems are integrated in their responses to any form of stress. It is well established that physical or psychosocial stress causes increased secretions of prolactin, growth hormones, thyroid, and gonadal hormones, in addition to ACTH. Endogenous opioids are secreted under such conditions and function as immunomodulators, while also elevating the pain threshold. Receptors for such hormones exist on immunocompetent cells, along with receptors for catecholamines, serotonin and acetylcholine. 

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