The luteinizing hormone response to luteinizing hormone-releasing hormone, prostaglandin E2 and naloxone is modulated by divergent sensitivity to testosterone feedback. 1985

U Schweiger, and K M Pirke

Testosterone (T) levels necessary to suppress LH secretion are reduced in starvation, and increased feedback sensitivity to T is therefore postulated. The luteinizing hormone (LH) response to naloxone (Nal) is more easily suppressed by starvation than is its response to prostaglandin E2 (PGE2) and to luteinizing hormone-releasing hormone (LRH). If the divergent suppressibility is due to altered feedback sensitivity in starvation, it should be feasible to reproduce this phenomenon in normally nourished rats by increasing T levels. Adult male Wistar rats were castrated and implanted with silicone capsules (0-2.6 cm) filled with T. Indwelling jugular cannulae were implanted. On days 4 to 8 post operation rats were injected iv with LRH (25-400 ng/kg body weight), PGE2 (0.05-1.0 mg/kg body weight) or Nal (0.5-50 mg/kg body weight). Blood samples were drawn before and 10, 20 and 30 min after injection. Results show that the response to Nal was already suppressed at medium T levels. The LH response to PGE2 was diminished to a greater extent than the response to LRH but was never completely suppressed by increasing steroid levels. These data are compatible with the hypothesis that steroid feedback sensitivity augments with increasing levels of regulation of the hypothalamic-pituitary-gonadal axis.

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
D007987 Gonadotropin-Releasing Hormone A decapeptide that stimulates the synthesis and secretion of both pituitary gonadotropins, LUTEINIZING HORMONE and FOLLICLE STIMULATING HORMONE. GnRH is produced by neurons in the septum PREOPTIC AREA of the HYPOTHALAMUS and released into the pituitary portal blood, leading to stimulation of GONADOTROPHS in the ANTERIOR PITUITARY GLAND. FSH-Releasing Hormone,GnRH,Gonadoliberin,Gonadorelin,LH-FSH Releasing Hormone,LHRH,Luliberin,Luteinizing Hormone-Releasing Hormone,Cystorelin,Dirigestran,Factrel,Gn-RH,Gonadorelin Acetate,Gonadorelin Hydrochloride,Kryptocur,LFRH,LH-RH,LH-Releasing Hormone,LHFSH Releasing Hormone,LHFSHRH,FSH Releasing Hormone,Gonadotropin Releasing Hormone,LH FSH Releasing Hormone,LH Releasing Hormone,Luteinizing Hormone Releasing Hormone,Releasing Hormone, LHFSH
D008297 Male Males
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
D009919 Orchiectomy The surgical removal of one or both testicles. Castration, Male,Orchidectomy,Castrations, Male,Male Castration,Male Castrations,Orchidectomies,Orchiectomies
D011458 Prostaglandins E (11 alpha,13E,15S)-11,15-Dihydroxy-9-oxoprost-13-en-1-oic acid (PGE(1)); (5Z,11 alpha,13E,15S)-11,15-dihydroxy-9-oxoprosta-5,13-dien-1-oic acid (PGE(2)); and (5Z,11 alpha,13E,15S,17Z)-11,15-dihydroxy-9-oxoprosta-5,13,17-trien-1-oic acid (PGE(3)). Three of the six naturally occurring prostaglandins. They are considered primary in that no one is derived from another in living organisms. Originally isolated from sheep seminal fluid and vesicles, they are found in many organs and tissues and play a major role in mediating various physiological activities. PGE
D011919 Rats, Inbred Strains Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding. August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D004343 Drug Implants Small containers or pellets of a solid drug implanted in the body to achieve sustained release of the drug. Drug Implant,Drug Pellet,Pellets, Drug,Drug Pellets,Implant, Drug,Implants, Drug,Pellet, Drug
D005246 Feedback A mechanism of communication within a system in that the input signal generates an output response which returns to influence the continued activity or productivity of that system. Feedbacks

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