Biomaterial Database

Do alpha-adrenergic mechanisms regulate spontaneous or opiate-modulated pulsatile luteinizing hormone secretion in man? 1983

J D Veldhuis, and A D Rogol, and F A Williams, and M L Johnson

Brain noradrenergic mechanisms participate in the excitatory control of episodic LH release in many experimental animals, including the nonhuman primate. In addition, augmentation of pulsatile LH release in the rodent in response to opiate receptor antagonists is dependent upon intact central noradrenergic pathways. The applicability of these tenets to humans is not known. We tested the excitatory influence of brain noradrenergic systems on pulsatile LH secretion in normal men by administering phenoxybenzamine (an irreversible, preferentially postsynaptic, alpha 1-receptor blocker) or alpha-methyldopa (an inhibitor of brain adrenergic transmission). Five normal men underwent repetitive (every 20 min) venous sampling for 8 h to characterize episodic LH release quantitatively under basal conditions and after the administration of naltrexone, a potent opiate receptor antagonist which stimulates puslatile LH release. Subjects received saline, phenoxybenzamine (1 mg/kg, iv, over 90 min), or alpha-methyldopa (250 mg, orally, every 6 h). The following parameters of spontaneous episodic LH secretion were not altered after phenoxybenzamine or alpha-methyldopa administration: mean and integrated serum LH concentrations, LH pulse frequency, LH pulse amplitude (percentage or milliinternational units per ml increment), and absolute peak serum LH values. In addition, the administration of adrenergic inhibitors did not impede the capacity of naltrexone to significantly augment pulsatile LH secretion in these subjects. We conclude that in the doses used, phenoxybenzamine and alpha-methyldopa do not alter spontaneous or opiate-modulated episodic LH release in normal men.

UI	MeSH Term	Description	Entries
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
D008750	Methyldopa	An alpha-2 adrenergic agonist that has both central and peripheral nervous system effects. Its primary clinical use is as an antihypertensive agent.	Methyldopate,alpha-Methyldopa,Aldomet,Alphamethyldopa,Apo-Methyldopa,Dopamet,Dopegit,Dopegyt,Dopergit,Hydopa,Meldopa,Nu-Medopa,Sembrina,alpha-Methyl-L-Dopa,Apo Methyldopa,Nu Medopa,alpha Methyl L Dopa,alpha Methyldopa
D009271	Naltrexone	Derivative of noroxymorphone that is the N-cyclopropylmethyl congener of NALOXONE. It is a narcotic antagonist that is effective orally, longer lasting and more potent than naloxone, and has been proposed for the treatment of heroin addiction. The FDA has approved naltrexone for the treatment of alcohol dependence.	Antaxone,Celupan,EN-1639A,Nalorex,Naltrexone Hydrochloride,Nemexin,ReVia,Trexan,EN 1639A,EN1639A
D010643	Phenoxybenzamine	An alpha-adrenergic antagonist with long duration of action. It has been used to treat hypertension and as a peripheral vasodilator.	Dibenylene,Dibenyline,Dibenziran,Dibenzylin,Dibenzyline,Dibenzyran,Phenoxybenzamine Hydrochloride,Hydrochloride, Phenoxybenzamine
D011942	Receptors, Adrenergic, alpha	One of the two major pharmacological subdivisions of adrenergic receptors that were originally defined by the relative potencies of various adrenergic compounds. The alpha receptors were initially described as excitatory receptors that post-junctionally stimulate SMOOTH MUSCLE contraction. However, further analysis has revealed a more complex picture involving several alpha receptor subtypes and their involvement in feedback regulation.	Adrenergic alpha-Receptor,Adrenergic alpha-Receptors,Receptors, alpha-Adrenergic,alpha-Adrenergic Receptor,alpha-Adrenergic Receptors,Receptor, Adrenergic, alpha,Adrenergic alpha Receptor,Adrenergic alpha Receptors,Receptor, alpha-Adrenergic,Receptors, alpha Adrenergic,alpha Adrenergic Receptor,alpha Adrenergic Receptors,alpha-Receptor, Adrenergic,alpha-Receptors, Adrenergic
D011957	Receptors, Opioid	Cell membrane proteins that bind opioids and trigger intracellular changes which influence the behavior of cells. The endogenous ligands for opioid receptors in mammals include three families of peptides, the enkephalins, endorphins, and dynorphins. The receptor classes include mu, delta, and kappa receptors. Sigma receptors bind several psychoactive substances, including certain opioids, but their endogenous ligands are not known.	Endorphin Receptors,Enkephalin Receptors,Narcotic Receptors,Opioid Receptors,Receptors, Endorphin,Receptors, Enkephalin,Receptors, Narcotic,Receptors, Opiate,Endorphin Receptor,Enkephalin Receptor,Normorphine Receptors,Opiate Receptor,Opiate Receptors,Opioid Receptor,Receptors, Normorphine,Receptors, beta-Endorphin,beta-Endorphin Receptor,Receptor, Endorphin,Receptor, Enkephalin,Receptor, Opiate,Receptor, Opioid,Receptor, beta-Endorphin,Receptors, beta Endorphin,beta Endorphin Receptor,beta-Endorphin Receptors
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults