Secretion of luteinizing hormone (LH) and pituitary receptors for LH-releasing hormone as modified by the proestrous surge of progesterone. 1984

J A Witcher, and K F Nearhoof, and M E Freeman

Pituitary glands of proestrous (PRO) rats display enhanced LH secretory response to LHRH when compared to pituitary glands of estrous (EST) rats. In addition proestrous pituitary glands display a self-potentiating (priming) response to LHRH, whereas estrous pituitary glands do not. This study addresses the role of the proestrous surge of progesterone in converting the proestrous-like LH secretory responses of the pituitary gland to those of estrus. Anterior pituitary glands were obtained from PRO and EST rats. In addition, Pro rats were treated with pentobarbital alone (PRO/PB) or with pentobarbital plus progesterone (PRO/PB-P4). Pentobarbital was given to prevent proestrous surges of LH and progesterone. Pentobarbital-treated animals were killed the day after treatment, estrus. Pituitary glands from each group were tested for LH secretory response in a superfusion chamber with exposure of two 15-min pulses of 10 nM LHRH separated by 90 min, or assayed for LHRH receptor content using iodinated D-Ala6-LHRH. Anterior pituitary glands from PRO rats secreted higher levels of LH than EST rats in response to an LHRH pulse. Only PRO anterior pituitary glands secreted priming responses to LHRH. Though anterior pituitary glands obtained from pentobarbital-treated rats showed LH responses of similar magnitude to anterior pituitary glands of PRO rats after initial LHRH challenge, they did not display priming responses. Progesterone replacement (PRO/PB-P4) led to depressed secretory responses when compared to PRO pituitary glands similar to EST rats. LHRH receptor concentrations in pituitary glands of EST rats was lower than those in pituitary glands of PRO rats. Depression of pituitary LHRH receptor concentration from proestrus to estrus was prevented by pentobarbital-treatment on proestrus. Estrus-like depression of receptor concentration was restored after progesterone treatment (PRO/PB-P4). These data suggest the LHRH receptor depression on estrus is a consequence of the secretion of progesterone on proestrus. Further, the declining magnitude of the in vitro LH-secretory response to LHRH follows a declining LHRH receptor concentration; however no correlation exists between receptor number and ability to prime.

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
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
D010902 Pituitary Gland A small, unpaired gland situated in the SELLA TURCICA. It is connected to the HYPOTHALAMUS by a short stalk which is called the INFUNDIBULUM. Hypophysis,Hypothalamus, Infundibular,Infundibular Stalk,Infundibular Stem,Infundibulum (Hypophysis),Infundibulum, Hypophyseal,Pituitary Stalk,Hypophyseal Infundibulum,Hypophyseal Stalk,Hypophysis Cerebri,Infundibulum,Cerebri, Hypophysis,Cerebrus, Hypophysis,Gland, Pituitary,Glands, Pituitary,Hypophyseal Stalks,Hypophyses,Hypophysis Cerebrus,Infundibular Hypothalamus,Infundibular Stalks,Infundibulums,Pituitary Glands,Pituitary Stalks,Stalk, Hypophyseal,Stalk, Infundibular,Stalks, Hypophyseal,Stalks, Infundibular
D011247 Pregnancy The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH. Gestation,Pregnancies
D011359 Proestrus A phase of the ESTROUS CYCLE that precedes ESTRUS. During proestrus, the Graafian follicles undergo maturation.
D011374 Progesterone The major progestational steroid that is secreted primarily by the CORPUS LUTEUM and the PLACENTA. Progesterone acts on the UTERUS, the MAMMARY GLANDS and the BRAIN. It is required in EMBRYO IMPLANTATION; PREGNANCY maintenance, and the development of mammary tissue for MILK production. Progesterone, converted from PREGNENOLONE, also serves as an intermediate in the biosynthesis of GONADAL STEROID HORMONES and adrenal CORTICOSTEROIDS. Pregnenedione,Progesterone, (13 alpha,17 alpha)-(+-)-Isomer,Progesterone, (17 alpha)-Isomer,Progesterone, (9 beta,10 alpha)-Isomer
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
D011956 Receptors, Cell Surface Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands. Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D011966 Receptors, LHRH Receptors with a 6-kDa protein on the surfaces of cells that secrete LUTEINIZING HORMONE or FOLLICLE STIMULATING HORMONE, usually in the adenohypophysis. LUTEINIZING HORMONE-RELEASING HORMONE binds to these receptors, is endocytosed with the receptor and, in the cell, triggers the release of LUTEINIZING HORMONE or FOLLICLE STIMULATING HORMONE by the cell. These receptors are also found in rat gonads. INHIBINS prevent the binding of GnRH to its receptors. GnRH Receptors,Gonadoliberin Receptors,Gonadorelin Receptors,Gonadotropin Releasing-Hormone Receptors,LHFSHRH Receptors,LHRH Receptors,Luliberin Receptors,Receptors, GnRH,Receptors, Gonadoliberin,Receptors, Gonadorelin,Receptors, Luliberin,Follicle Stimulating Hormone-Releasing Hormone Receptors,GnRH Receptor,Gonadorelin Receptor,Gonadotropin-Releasing Hormone Receptor,LHRH Receptor,Luteinizing Hormone Releasing Hormone Receptors,Luteinizing Hormone Releasing-Hormone Receptor,Receptor, LHRH,Receptors, Gonadotropin Releasing-Hormone,Receptors, LHFSHRH,Follicle Stimulating Hormone Releasing Hormone Receptors,Gonadotropin Releasing Hormone Receptor,Gonadotropin Releasing Hormone Receptors,Hormone Receptor, Gonadotropin-Releasing,Luteinizing Hormone Releasing Hormone Receptor,Receptor, GnRH,Receptor, Gonadorelin,Receptor, Gonadotropin-Releasing Hormone,Receptors, Gonadotropin Releasing Hormone,Releasing-Hormone Receptors, Gonadotropin
D004971 Estrus The period in the ESTROUS CYCLE associated with maximum sexual receptivity and fertility in non-primate female mammals.

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