Altered glycosylation of pituitary gonadotropins in anorexia nervosa: an alternative explanation for amenorrhea.
To investigate the relevance of glycoprotein polymorphism to gonadotropin bioactivity in vivo, plasma follicle-stimulating hormone (FSH) and luteinizing hormone (LH), 17 beta-estradiol (E2), testosterone and sex hormone binding globulin (SHBG) levels in 17 amenorrheic women affected with anorexia nervosa (14-29 years) and 10 age-matched normally cycling women were evaluated. Plasma FSH and LH levels were assayed using radioimmunoassay (RIA) and immunoradiometric assay (IRMA) methods, before and after concanavalin A-Sepharose (Con A) affinity chromatography. Significant RIA-IRMA differences in FSH and LH plasma values were present only in women with anorexia nervosa (p < 0.005). Moreover, in these patients both FSH and LH showed a reduced binding to the Con A, expressed as a percentage of unbound, suggesting altered glycosylation of these moieties. In conclusion, these findings hypothesize the involvement of glycosylation polymorphism in RIA-IRMA differences; support the usefulness of both RIA and IRMA methods in FSH and LH evaluation, before and after Con A chromatography; and suggest a new pathogenetic pathway to explain amenorrhea in anorexia nervosa.
Tommaselli
A P
AP
Chair of Endocrinology, CEOS, National Research Council (CNR), Naples, Italy.
Valentino
R
R
Savastano
S
S
Randazzo
G
G
Scalfi
L
L
Contaldo
F
F
Dorato
M
M
Lombardi
G
G
D000293:Adolescent; D000328:Adult; D000568:Amenorrhea / Q000097:blood / Q000209:etiology* / Q000378:metabolism*; D000856:Anorexia Nervosa / Q000097:blood / Q000150:complications* / Q000378:metabolism*; D002846:Chromatography, Affinity; D003208:Concanavalin A; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006031:Glycosylation; D006062:Gonadotropins / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D015592:Immunoradiometric Assay; D007986:Luteinizing Hormone / Q000097:blood; D010902:Pituitary Gland / Q000737:chemistry / Q000378:metabolism; D011863:Radioimmunoassay; D012738:Sex Hormone-Binding Globulin / Q000032:analysis
D006062:Gonadotropins; D012738:Sex Hormone-Binding Globulin; D003208:Concanavalin A; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone