Plasma Melatonin Concentrations in Precocious and Pseudoprecocious Puberty

Abstract

Hormones of the pineal gland are supposed to have antigonadotropic effects in animals. In man the interrelationship between the pineal hormones, gonadotropins and sex hormones are not sufficiently investigated. On this account we studied diurnal plasma patterns of melatonin in 10 girls with precocious puberty as well as in 10 children with pseudoprecocious puberty. Melatonin was determined by radioimmunoassay using a recently raised antiserum. - In spite of high gonadotropins (LH-RH-test: LH-peak 23.2±11.2 and FSH-peak 10.8±2.7 μg/1) high plasma melatonin levels were observed in true precocious puberty (range: 5-45 pg/ml during the day and 85-285 pg/ml at night). These values were similar to melatonin concentrations in a control group of healthy children at the same stage of puberty (67±15(SE) during the day and 125±16(SE) pg/ml at night. - In pseudoprecocious puberty with low gonadotropins due to high an-drogen and 17α -hydroxyprogesterone levels in congenital adrenal hyperplasia (CAH) melatonin plasma levels were in the same range found in precocious puberty. Melatonin ranged between undetectable values and 73 pg/ml during the day and increased up to 375 pg/ml at night. - In precocious puberty gonadotropin values seem to increase independently of plasma melatonin concentrations which conversely are not altered by high androgen levels in pseudoprecocious puberty due to CAH.