6) http:/// pubmed/1366242
Ir J Med Sci. 1992 Dec;161(12):684-6. TSH as an index of L-thyroxine replacement and suppression therapy. Igoe D1, Duffy MJ, McKenna TJ.
When hypothalamic-pituitary function is normal, serum TSH levels measured by ultrasensitive assay yield bioassays of endogenous thyroid action and thus provide an ideal index of thyroid secretion and its relationship to fluctuating endogenous thyroid levels. It is theoretically possible that patients receiving exogenous L-thyroxine for primary hypothyroidism should have suppressed TSH levels if physiological needs are constantly met . To examine this possibility free thyroxine, FT4 and TSH were measured in 90 clinically euthyroid patients receiving treatment with L-thyroxine for primary hypothyroidism. TSH levels were normal in 44, suppressed in 16 and elevated in 30 patients. FT4 levels were normal in 68, elevated in 13 and suppressed in 9 patients. Normal TSH levels were associated with normal FT4 levels in % of patients, elevated FT4 levels in % and low FT4 in %. Suppressed TSH levels were associated with elevated FT4 levels in % of patients and normal FT4 levels in %. When FT4 levels were normal, however, TSH levels were normal in only % and abnormal in %. We also examined the possibility that FT4 levels may remain within normal range when TSH is suppressed during L-thyroxine treatment for goitre or cancer. FT4 and TSH were measured in 45 patients on L-thyroxine as TSH suppression treatment. TSH was suppressed in 23 patients (%), normal in 20 (%) and elevated in 2 (%). When TSH was suppressed, FT4 was elevated in % but normal in % of patients.(ABSTRACT TRUNCATED AT 250 WORDS)
Early versus delayed treatment: For men who need (or will eventually need) hormone therapy, such as men whose PSA levels are rising after surgery or radiation or men with advanced prostate cancer who don’t yet have symptoms, it’s not always clear when it is best to start hormone treatment. Some doctors think that hormone therapy works better if it’s started as soon as possible, even if a man feels well and is not having any symptoms. Some studies have shown that hormone treatment may slow the disease down and perhaps even help men live longer.
A far more common cause of excess production of androgens in women is polycystic ovary syndrome (PCOS; also called Stein-Leventhal syndrome ). This syndrome is characterized by excess androgens and the presence of a menstrual disorder. Androgen excess often manifests as hirsutism, with or without increased serum concentrations of one or more androgens. Some women have increased serum androgen concentrations and no hirsutism. A variety of menstrual disorders have been associated with PCOS, including oligomenorrhea, amenorrhea, anovulation, and infertility . An ultrasound may reveal multiple ovarian cysts. Many women with this syndrome are obese . Another characteristic feature of PCOS is tissue resistance to the action of insulin . This is expected in obese women, but it is also present in nonobese women with the syndrome. Insulin resistance leads to an increase in insulin secretion (hyperinsulinemia), which is thought to stimulate ovarian androgen production. Hyperinsulinemia also decreases the production of sex hormone-binding globulin so that more of the testosterone in the serum is free and accessible to the tissues. In addition, the conversion of androgens to estrogens in adipose tissue is increased (particularly in obese women), which leads to a small sustained increase in the secretion of luteinizing hormone and to the suppression of ovulation .