ABSTRACT
Effects of prenatal hyperhomocysteinemia on hypothalamic regulation of estrous cycles were studied in female rats. In mature rats exposed to prenatal hyperhomocysteinemia, changes in the catecholamine content in hypothalamic areas responsible for the formation of the preovulatory surge of gonadotropin-releasing hormone were revealed: the level of norepinephrine in the medial preoptic area decreased and concentration of dopamine in the median eminence with arcuate nuclei increased. Administration of melatonin attenuated the observed changes, which can be related to neuroprotective effects of this hormone determined by its antioxidant properties.
Subject(s)
Antioxidants/pharmacology , Estrous Cycle/drug effects , Hyperhomocysteinemia/prevention & control , Melatonin/pharmacology , Neuroprotective Agents/pharmacology , Prenatal Exposure Delayed Effects/prevention & control , Animals , Arcuate Nucleus of Hypothalamus/drug effects , Arcuate Nucleus of Hypothalamus/metabolism , Arcuate Nucleus of Hypothalamus/physiopathology , Catecholamines/metabolism , Female , Gonadotropin-Releasing Hormone/metabolism , Hyperhomocysteinemia/chemically induced , Hyperhomocysteinemia/metabolism , Hyperhomocysteinemia/physiopathology , Luteinizing Hormone/metabolism , Median Eminence/drug effects , Median Eminence/metabolism , Median Eminence/physiopathology , Methionine/adverse effects , Methionine/metabolism , Norepinephrine/metabolism , Pregnancy , Prenatal Exposure Delayed Effects/chemically induced , Prenatal Exposure Delayed Effects/metabolism , Prenatal Exposure Delayed Effects/physiopathology , Preoptic Area/drug effects , Preoptic Area/metabolism , Preoptic Area/physiopathology , Progesterone/metabolism , Rats , Rats, WistarABSTRACT
The article presents a detailed analysis of correlations between the content of a variety of biogenic amines in the hypothalamic structures responsible for the luteinizing hormone releasing hormone synthesis and secretion (the medial preoptic area and median eminence) and such independent factors as total L-homocysteine plasma level elevation induced by L-methionine loading and aging. Both a nature and a pattern of changes in oxidative stress profile were evaluated. It was shown that ageing, when compared to hyperhomocysteinemia, is a determining factor influencing biogenic amine content in the studied hypothalamic structures. Unlike antioxidant defense system profile, considerable changes in macromolecule oxidative modification were not found, which evidences a balanced activity of pro- and antioxidant systems in the hypothalamus.
Subject(s)
Aging , Biogenic Amines/metabolism , Gonadotropin-Releasing Hormone , Homocysteine , Hyperhomocysteinemia/metabolism , Hypothalamus , Aging/blood , Aging/metabolism , Animals , Female , Gonadotropin-Releasing Hormone/biosynthesis , Gonadotropin-Releasing Hormone/metabolism , Homocysteine/blood , Homocysteine/metabolism , Hypothalamus/metabolism , Hypothalamus/pathology , Oxidative Stress/physiology , Rats , Rats, WistarABSTRACT
The data presented have shown the different effect of hyperhomocysteinemia (induced by 0,12-0,15 mg of methionine loading per os during 30 days) on monoamines content in hypothalamus and hippocampus of young (6-7 month) and old (20-22 month) female rats. It has been established that the level of catecholamines (noradrenaline, dopamine), 5 oxitryptamine and 5 oxyindolacetic acid in hypothalamic areas responsible for synthesis and secretion of gonadoliberin (medial preoptic area and medial eminence with arcuate nuclei) is considerable less in old animals compared with young ones. These data are in agreement with the low content of gonadoliberin found by us in medial eminence with arcuate nuclei. It has been also shown the decreased level of monoamines level in hippocampus of old rats, which does not depend on methionine loading. However in hippocampus of young animals hyperhomocysteinemia induced a noticeable reduction of noradrenaline and 5 oxyindolacetic acid, which can lead to weakening of animal's cognitive function.
