The sex-dependent differentiation of monoamine oxidase (MAO) in the hypothalamus of 60-day-old, Charles River rats was found to involve only type A (MAO-A), and not type B (MAO-B) enzyme. In vivo inhibition of type A by clorgyline, and type B by (--)deprenyl, however, tended to decrease the specific activity of both types of MAO to a smaller extent in the female than in the male hypothalamus. When masculinization was prevented by neonatal administration of estradiol (E) to males, hypothalamic MAO-A and MAO-B activities increased in both control and MAO-inhibited rats. Androgenization of females, however, had little effect on the MAO activity. Whereas the effects of neonatal estrogenization were attributable neither to a direct influence of E nor to a sexual difference in the peripheral clearance of the MAO-inhibitor used, single, high doses of steroids to adult, but not to newborn rats, did acutely affect the kinetics of MAO-A. The activity of MAO-A was also decreased by high concentrations of E or TS in vitro. The imprinting for patterns of hypothalamic MAO-A and MAO-B in the two sexes results, probably, from genetic predetermination. Neonatal changes in the homeostasis of gonadal hormones may result in type-MAO nonspecific effects in adulthood, whereas the short-term effects of high concentrations of steroids may be selective for the A form.
|Titolo:||Gonadal influences on the sexual differentiation of monoamine oxidase type A and B activities in the rat brain|
SPARATORE, ANNA CONCETTINA (Penultimo)
|Parole Chiave:||Animals; Hypothalamus; Sex Factors; Brain; Clorgyline; Monoamine Oxidase; Estradiol; Sexual Maturation; Rats; Testosterone; Succinate Dehydrogenase; Kinetics; Isoenzymes; Female; Male|
|Settore Scientifico Disciplinare:||Settore BIO/14 - Farmacologia|
|Data di pubblicazione:||set-1981|
|Digital Object Identifier (DOI):||10.1111/j.1471-4159.1982.tb12535.x|
|Appare nelle tipologie:||01 - Articolo su periodico|