The objective was to determine how estradiol (0 vs 1 mg) and changes in the dosage of luteinizing hormone releasing hormone (LHRH; 1,000 ng/steer vs 1 ng/kg body weight) and frequency of LHRH injection (25 vs 50 min) affect LH and follicle stimulating hormone (FSH) release in steers. In steers pretreated with estradiol peak concentrations of LH in serum after LHRH averaged 14.4 ng/ml, which was...

Recently, specific binding sites for luteinizing hormone releasing hormone (LHRH) and its analogues have been demonstrated in biopsy samples of human epithelial ovarian cancer. Their biological significance remained obscure. In this study we ascertained whether such LHRH-binding sites are also present in the human epithelial ovarian cancer cell lines EFO-21 and EFO-27 and if they could mediate ...

The therapeutic options for the treatment of androgen-independent prostatic cancers are rather limited; this is mainly because our understanding of the local mechanisms involved in the control of androgen-independent proliferation of the tumor is still very poor. The present experiments have been performed to verify whether luteinizing hormone-releasing hormone (LHRH) agonists may possess a dir...

The objectives of this study were 1) to evaluate the ability of trenbolone acetate (TBA) administered in tandem with LHRH immunization to suppress reproductive function in bulls and 2) to examine the effects of LHRH and androgen (TBA) signaling on pituitary gland function. Forty-four Angus × Hereford crossbred calves (BW=225 ± 2 kg; age=187 ± 6 d) received castration, LHRH immunization, or TBA ...

During development, a subpopulation of olfactory neurons transiently expresses GABA. The spatiotemporal pattern of GABAergic expression coincides with migration of luteinizing hormone-releasing hormone (LHRH) neurons from the olfactory pit to the CNS. In this investigation, we evaluated the role of GABAergic input on LHRH neuronal migration using olfactory explants, previously shown to exhibit ...

Results of previous studies suggest that altered patterns of LHRH neurosecretion contribute to attenuated LH surges and the eventual cessation of ovulation in aging female rats. The present study compared evidence of LHRH neuronal activation in conjunction with the preovulatory and steroid-induced LH surge in young and middle-aged animals to determine whether age-related alterations could be de...

In order to gain insight into sensory processing modulating reproductive behavioral and endocrine changes, we have aimed at identifying afferent pathways to neurons synthesizing luteinizing hormone-releasing hormone (LHRH, also known as gonadotropin-releasing hormone [GnRH]), a key neurohormone of reproduction. Injection of conditional pseudorabies virus into the brain of an LHRH::CRE mouse lin...

The synaptic interactions between catecholaminergic terminals and luteinizing hormone releasing hormone (LHRH)-containing neurons in the medial preoptic area of the rat was studied by electron microscopy using LHRH immunocytochemistry combined with 5-hydroxydopamine labeling or autoradiography after injection of 3H-dopamine or 3H-noradrenaline in the same tissue section. Axon terminals labeled ...

The present study examines the role of cerebroventricular administered (IIIrd ventricle) galanin on LHRH and LH release in adult and immature male rats. In both age groups, galanin stimulated LHRH synthesis and release from the hypothalamus, leading to a higher release of pituitary LH which in turn increased plasma LH levels. Galantide, a galanin receptor blocker, on the other hand, drastically...

Our working hypothesis was that synthesis and release of LH, but not FSH, were solely dependent on LHRH. Twenty ovariectomized (OVX) ewes were randomly assigned to one of five treatments (n = 4 per group). Ewes were administered a low (10 micrograms/kg) or high (100 micrograms/kg) dose of LHRH antagonist (LHRH-Ant) at 24-h intervals for 3 or 6 days. Control ewes received vehicle (5% mannitol) a...