Biomaterial Database

Naloxone does not reverse the inhibitory effect of morphine on luteinizing hormone secretion in prepubescent male rats. 1993

T J Cicero, and B Nock, and L O'Connor

Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri.

Morphine and naloxone exert age-dependent effects on secretion of luteinizing hormone (LH) in the male rat. Morphine suppresses LH secretion at very early stages of development, well before puberty, whereas naloxone does not increase LH until after puberty. The mechanisms underlying these age-dependent effects of opiates on the hypothalamic-pituitary-gonadal axis in pre- and postpubertal rats are poorly understood at the present time. The purpose of the present studies was to examine one plausible explanation of these effects: that morphine and naloxone act through different receptors in the pubescent male rat than they do in adults to influence LH secretion. Specifically, we examined whether naloxone blocks the effects of morphine on LH in prepubescent and adult rats which would be anticipated if both drugs were exerting their effects on LH via the same opiate receptor. Surprisingly, we found that naloxone did not reverse the effects of morphine on serum LH levels in the prepubescent animal, although it fully reversed this effect in adults. This non-naloxone-reversible effect of morphine appeared to be specific to LH, since naloxone antagonized morphine's effects on several other hormones (e.g., prolactin and corticosterone) and completely attenuated morphine's antinociceptive activity in prepubescent rats. Additionally, naloxone precipitated a withdrawal syndrome in the prepubescent morphine-dependent animal that was quantitatively and qualitatively the same as in adults.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D007030	Hypothalamo-Hypophyseal System	A collection of NEURONS, tracts of NERVE FIBERS, endocrine tissue, and blood vessels in the HYPOTHALAMUS and the PITUITARY GLAND. This hypothalamo-hypophyseal portal circulation provides the mechanism for hypothalamic neuroendocrine (HYPOTHALAMIC HORMONES) regulation of pituitary function and the release of various PITUITARY HORMONES into the systemic circulation to maintain HOMEOSTASIS.	Hypothalamic Hypophyseal System,Hypothalamo-Pituitary-Adrenal Axis,Hypophyseal Portal System,Hypothalamic-Pituitary Unit,Hypothalamic Hypophyseal Systems,Hypothalamic Pituitary Unit,Hypothalamo Hypophyseal System,Hypothalamo Pituitary Adrenal Axis,Portal System, Hypophyseal
D007986	Luteinizing Hormone	A major gonadotropin secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Luteinizing hormone regulates steroid production by the interstitial cells of the TESTIS and the OVARY. The preovulatory LUTEINIZING HORMONE surge in females induces OVULATION, and subsequent LUTEINIZATION of the follicle. LUTEINIZING HORMONE consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the three pituitary glycoprotein hormones (TSH, LH and FSH), but the beta subunit is unique and confers its biological specificity.	ICSH (Interstitial Cell Stimulating Hormone),Interstitial Cell-Stimulating Hormone,LH (Luteinizing Hormone),Lutropin,Luteoziman,Luteozyman,Hormone, Interstitial Cell-Stimulating,Hormone, Luteinizing,Interstitial Cell Stimulating Hormone
D008297	Male		Males
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D009020	Morphine	The principal alkaloid in opium and the prototype opiate analgesic and narcotic. Morphine has widespread effects in the central nervous system and on smooth muscle.	Morphine Sulfate,Duramorph,MS Contin,Morphia,Morphine Chloride,Morphine Sulfate (2:1), Anhydrous,Morphine Sulfate (2:1), Pentahydrate,Oramorph SR,SDZ 202-250,SDZ202-250,Chloride, Morphine,Contin, MS,SDZ 202 250,SDZ 202250,SDZ202 250,SDZ202250,Sulfate, Morphine
D009270	Naloxone	A specific opiate antagonist that has no agonist activity. It is a competitive antagonist at mu, delta, and kappa opioid receptors.	MRZ 2593-Br,MRZ-2593,Nalone,Naloxon Curamed,Naloxon-Ratiopharm,Naloxone Abello,Naloxone Hydrobromide,Naloxone Hydrochloride,Naloxone Hydrochloride Dihydride,Naloxone Hydrochloride, (5 beta,9 alpha,13 alpha,14 alpha)-Isomer,Naloxone, (5 beta,9 alpha,13 alpha,14 alpha)-Isomer,Narcan,Narcanti,Abello, Naloxone,Curamed, Naloxon,Dihydride, Naloxone Hydrochloride,Hydrobromide, Naloxone,Hydrochloride Dihydride, Naloxone,Hydrochloride, Naloxone,MRZ 2593,MRZ 2593 Br,MRZ 2593Br,MRZ2593,Naloxon Ratiopharm
D009292	Narcotic Antagonists	Agents inhibiting the effect of narcotics on the central nervous system.	Competitive Opioid Antagonist,Narcotic Antagonist,Opioid Antagonist,Opioid Antagonists,Opioid Receptor Antagonist,Opioid Reversal Agent,Competitive Opioid Antagonists,Opioid Receptor Antagonists,Opioid Reversal Agents,Agent, Opioid Reversal,Agents, Opioid Reversal,Antagonist, Competitive Opioid,Antagonist, Narcotic,Antagonist, Opioid,Antagonist, Opioid Receptor,Antagonists, Competitive Opioid,Antagonists, Narcotic,Antagonists, Opioid,Antagonists, Opioid Receptor,Opioid Antagonist, Competitive,Opioid Antagonists, Competitive,Receptor Antagonist, Opioid,Receptor Antagonists, Opioid,Reversal Agent, Opioid,Reversal Agents, Opioid
D009619	Nociceptors	Peripheral AFFERENT NEURONS which are sensitive to injuries or pain, usually caused by extreme thermal exposures, mechanical forces, or other noxious stimuli. Their cell bodies reside in the DORSAL ROOT GANGLIA. Their peripheral terminals (NERVE ENDINGS) innervate target tissues and transduce noxious stimuli via axons to the CENTRAL NERVOUS SYSTEM.	Pain Receptors,Receptors, Pain,Nociceptive Neurons,Neuron, Nociceptive,Neurons, Nociceptive,Nociceptive Neuron,Nociceptor,Pain Receptor
D010913	Pituitary-Adrenal System	The interactions between the anterior pituitary and adrenal glands, in which corticotropin (ACTH) stimulates the adrenal cortex and adrenal cortical hormones suppress the production of corticotropin by the anterior pituitary.	Pituitary Adrenal System,Pituitary-Adrenal Systems,System, Pituitary-Adrenal,Systems, Pituitary-Adrenal
D011388	Prolactin	A lactogenic hormone secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). It is a polypeptide of approximately 23 kD. Besides its major action on lactation, in some species prolactin exerts effects on reproduction, maternal behavior, fat metabolism, immunomodulation and osmoregulation. Prolactin receptors are present in the mammary gland, hypothalamus, liver, ovary, testis, and prostate.	Lactogenic Hormone, Pituitary,Mammotropic Hormone, Pituitary,Mammotropin,PRL (Prolactin),Hormone, Pituitary Lactogenic,Hormone, Pituitary Mammotropic,Pituitary Lactogenic Hormone,Pituitary Mammotropic Hormone