Thyroid and Hormones

Estrogen prevents thyroid autoimmunity; progesterone increases thyroid autoimmunity

The administration of estrogen or progesterone to groups of 4 week old rats over a period of 15 weeks significantly altered the course of the events leading to the induction of this condition. Estrogen administered repeatedly at dose levels of 1 microgram and 10 micrograms/100 g body weight resulted in partial suppression of thyroiditis with a corresponding change in the incidence of antibodies to thyroglobulin. Similarly, estrogen administered by a single implantation had a suppressive effect on the development of autoimmunity in ovariectomized female rats. In contrast to the inhibitory effects of estrogen, the repeated administration of progesterone at a dose of 250 ng and 1,500 micrograms/100 g body weight appeared to augment the levels of autoimmunity. It is concluded that the differential susceptibility to the induction of autoimmunity by thymectomy and irradiation is the direct consequence of sex hormonal influences. Furthermore, the higher incidence of the disease in the female would appear to be determined by the balance between the activity of estrogen and progesterone which would further appear to have antagonistic influences in this particular situation.

http://www.ncbi.nlm.nih.gov/pubmed/6360435

Estrogen blocks thyroid hormone production

Thyroid stimulating hormone production is blunted by somatostatin (SRIH), rising levels of glucocorticoids (ex. cortisol) and sex hormones (estrogen and testosterone), and excessively high blood iodide.

http://www.acronymdict.com/index/tag/tag/Protein/id/94290

Estrogen and Miscarriage

Testosterone and Miscarriage

Stress and Miscarriage

Estrogen blocks thyroid hormones by increasing the production of TBG

If thyroid binding globulin (TBG) level is high, which can occur when estrogen levels are high, the TBG will bind more thyroid hormone, decreasing the free hormone available in the blood, which leads to stimulation of TSH, and the production of more thyroid hormone. T4 circulates in the blood in two forms: 1) T4 bound to proteins that prevent the T4 from entering the various tissues that need thyroid hormone and 2) free T4, which does enter the various target tissues to exert its effects.

http://en.wikipedia.org/wiki/Thyroxine-binding_globulin

Estrogen linked to autoimmune disease

Treatment with estrogen accelerates lupus in mice.

http://linkinghub.elsevier.com/retrieve/pii/000887499290236I

Estrogens boost T4 and T3 production

As expected, estrogens induced an increase in total T4 and total T3 values.

http://www.ncbi.nlm.nih.gov/pubmed/11383317

Progesterone promotes T4 to T3 conversion

Progesterone and pregnenolone tend to increase thyroid hormone effects because they promote the conversion of T4 to the more active T3. Estrogen has the opposite effect on thyroid hormone conversion.

http://www.drkaslow.com/html/thyroid.html

Progesterone and Miscarriage

Prolactin promotes autoimmunity

Prolactin has an immunostimulatory effect and promotes autoimmunity: prolactin impairs the negative selection of autoreactive B lymphocytes occurring during B cell maturation into fully functional B cells. Prolactin has an anti-apoptotic effect, enhances proliferative response to antigens and mitogens and enhances the production of immunoglobulins and autoantibodies. Hyperprolactinemia is observed in multi-organ and organ specific autoimmune diseases like Hashimoto's thyroiditis.

http://linkinghub.elsevier.com/retrieve/pii/S1568997206002096