Reproductive axis response to repeated lipopolysaccharide administration in peripubertal female rats.

Immune system disorders are often accompanied by alterations in the reproductive axis. Several reports have shown that administration of bacterial lipopolysaccharide (LPS) has central inflammatory effects and activates cytokine release in the hypothalamus where the luteinizing hormone releasing hormone (Gn-RH) neurons are located. The present study was designed to investigate the effect of repeated LPS administration on the neuroendocrine mechanisms of control of the reproductive axis in peripubertal female rats (30-day-old rats).

Impact of gestational and lactational phthalate exposure on hypothalamic content of amino acid neurotransmitters and FSH secretion in peripubertal male rats.

This study investigated the effect of the pre- and perinatal exposure to di-(2-ethylhexyl) phthalate (DEHP) on the neuroendocrine parameters that regulate reproduction in peripubertal male rats. DEHP at dose of 3 and 30mg/kg bw/day was administered orally to female rat since pregnancy onset until weaning. The male litters were sacrificed at 30 days of age to determine gonadotropin serum level and the hypothalamic contents of the amino acids aspartate and gamma-aminobutyric acid.

Low dose 4-MBC effect on neuroendocrine regulation of reproductive axis in adult male rats.

4-Methylbenzylidene camphor (4-MBC) is an ultraviolet absorbent. The objective of this paper was to evaluate the effect of 4-MBC low-dose exposure on the neuroendocrine reproductive regulation in male rats. Wistar male adult rats were injected sc.

Effect of bacterial lipopolysaccharide on the reproductive axis of prepubertal and peripubertal female rats. Ontogenic changes in the immune-neuroendocrine interactions.

The immune, endocrine and nervous systems are closely interrelated, which allows the organism to respond to different types of stress such as infection. Chronic infectious and inflammatory conditions are often accompanied by an impaired reproductive function. Leptin, a hormone produced by adipose tissue, exerts a regulatory function on the reproductive axis.

Leptin stimulates LH secretion in peripubertal male rats through NMDA receptors.

Leptin, a peptide hormone secreted by adipocytes that has been proposed as a metabolic signal in the reproductive system, appears to be linked to the different neuroendocrine processes involved in the onset of puberty. We studied the ontogenic effect of administration of leptin (30 mg/kg i.p.

Effect of leptin on LH levels and hypothalamic release of GnRH. Its relationship with the hypothalamic neurotransmitter amino acids system in adult male rats.

The objective of the present paper was to determine the effect of leptin on the reproductive axis in adult male rats, as well as the hypothalamic mechanisms involved in this effect. For this purpose, we studied the in vivo effect of leptin in adult male rats on serum LH levels, and the in vitro effect on hypothalamic GnRH and amino acid neurotrasmitter release. For in vivo experiments, animals were injected i.

Hypothalamic nitric oxide synthase activity during sexual maturation in female rats. Effects of estrogens.

Objectives: To determine the hypothalamic activity of nitric oxide synthase (NOS, the enzyme involved in the synthesis of nitric oxide NO) during sexual maturation in prepubertal (15 days old) and peripubertal female rats (30 days old) as well as the effect of estradiol administration on this neurotransmitter system.

Methods: Hypothalamic samples containing the anterior preoptic and medial basal areas (APOA-MBH) were homogenized with HEPES 20 mM, pH = 7.4 and NOS activity was determined in APO-MBH after 10 minutes of incubation by the conversion of 14C arginine to 14C citrulline.

Effects of gabaergic and serotoninergic systems on hypothalamic content of catecholamines during sexual development in female rats.

Objectives: The aim of the present investigation was to determine whether the catecholaminergic system is involved in gabaergic and serotoninergic effects on gonadotrophin secretion during sexual development. To this end, we studied the effect of GABAergic and serotoninergic systems on hypothalamic catecholamine content at different stages of sexual development.

Methods: The effect of GABA A and GABA B agonists and 5-hydroxy-L-tryptophan on hypothalamic noradrenaline and dopamine content were determined in prepubertal (16 days old) and peripubertal (30 days old) rats.

Changes in the effect of testosterone on hypothalamic nitric oxide synthetase during sexual maturation. Its relationship with GnRH release.

Objectives: To determine the effect of testosterone administration to prepubertal (15 days old) and peripubertal rats (30 days old) on hypothalamic nitric oxide synthetase (NOS), and GnRH release.

Methods: Hypothalamic samples containing the anterior preoptic and medial basal areas (APO-MBH) were incubated for 30 minutes in 500 l of Earle's medium with glucose (1 mg/ml) and bacitracin (20 mM). GnRH was determined by RIA in the medium and NOS activity was determined in APO-MBH after 10 min of incubation by the conversion of (14) C arginine to (14) C citrulline.

Effects of aproteic diet on hypothalamic-pituitary- gonadal regulation in the male rat.

The effect of an aproteic diet (Ap) on the reproductive axis in young male rats was studied. Also the refeeding effect at different times after the aproteic diet was studied. The Ap diet was given during 21 days.