Serum calcitonin is a hormone secreted by thyroid follicular cells that, when elevated for some reason, increases the excretion of calcium by the kidneys and lowers blood calcium concentrations. Endemic goiter is a type of goiter. In the early stage, there are no obvious clinical symptoms, and the thyroid gland is mildly or moderately diffusely enlarged, soft in texture and without pressure pain. So, how to differentially diagnose an increased serum calcitonin level? The following is a brief introduction: Calcitonin is a tridodecapeptide containing a disulfide bond with a molecular weight of 3400. the concentration of calcitonin in normal human serum is 10-20ng/L, with a plasma half-life of less than 1h, and is mainly degraded and excreted in the kidney. The main effect of calcitonin is to lower blood calcium and blood phosphorus, and its main target organ is bone, and it also has a certain effect on kidney. Low serum testosterone concentration: The effect of hypogonadism and reduced testosterone levels on men’s health has been a controversial issue. Although studies have confirmed that high doses of testosterone or other exogenous androgen intake can be detrimental to health, low serum testosterone levels may predict increased mortality in older men. Low testosterone levels in blood may actually be a risk factor for coronary atherosclerosis. Testosterone, also known as testosterone, testosterone or testosterone, is a steroid hormone that is secreted by the testes in men or the ovaries in women, and to a lesser extent by the adrenal glands. It is the main male sex hormone and anabolic hormone. The amount of testosterone secreted by adult males is 20 times greater than that secreted by adult females. In the follicular phase of the normal female menstrual cycle, the average serum testosterone concentration is 0.43ng/ml and the high limit is 0.68ng/ml. Significantly elevated serum testosterone concentration: In the follicular phase of the normal menstrual cycle, the average serum testosterone concentration is 0.43ng/ml and the high limit is 0.68ng/ml, if it exceeds 0.7ng/m1 (equal to 2.44nmol/L), it is called hyper testosteronemia, or hyperandrogenemia. The ovaries and adrenal cortex can synthesize cholesterol from acetic acid, or absorb cholesterol from the blood as a substrate to synthesize steroid hormones, which are secreted into the blood circulation. The main androgens in the blood circulation are dehydroepiandrosterone sulfate (DHEAS), dehydroepiandrosterone (DHEA), androstenedione (Delta;4A), testosterone (T) and dihydrotestosterone (DHT). Hypertestosteronemia is formed when the levels of these hormones, especially testosterone, are too high in the blood.