Prostaglandin synthesis in rabbit graafian follicles in vitro. Effect of luteinizing hormone and cyclic AMP

1974 ◽  
Vol 7 (4) ◽  
pp. 269-283 ◽  
Author(s):  
John M. Marsh ◽  
Norman S.T. Yang ◽  
William J. LeMaire
Keyword(s):  
Luteinizing Hormone ◽  
Cyclic Amp ◽  
Prostaglandin Synthesis ◽  
Vitro Effect

In vitro effect of prostaglandins on the accumulation of cyclic AMP in the avian oviduct

1987 ◽  
Vol 66 (2) ◽  
pp. 244-247 ◽  
Author(s):  
Elikplimi K. Asem ◽  
Herbert Todd ◽  
Frank Hertelendy
Keyword(s):  
Cyclic Amp ◽  
Vitro Effect

Thyroid hormone regulation of the catecholamine effects in human adipose tissue

1981 ◽  
Vol 96 (1) ◽  
pp. 65-69 ◽  
Author(s):  
Peter Arner ◽  
Anders Wennlund ◽  
Jan Östman
Keyword(s):  
Adipose Tissue ◽  
Thyroid Hormone ◽  
Cyclic Amp ◽  
Thyroid Hormones ◽  
Hormone Level ◽  
Normal Weight ◽  
Thyroid Hormone Level ◽  
Hormone Regulation ◽  
Vitro Effect

Abstract. The possibility of a relationship between the thyroid hormone level and the peripheral action of catecholamines was examined in 4 normal-weight and 19 obese euthyroid subjects as well as in 27 hyperthyroid subjects by comparing the serum thyroid hormone level and the in vitro effect of catecholamines on lipolysis and cyclic AMP accumulation in adipose tissue incubated with and without isopropyl noradrenaline (ISNA) or noradrenaline (NA). ISNA- and NA-induced rates of lipolysis and cyclic AMP production were significantly correlated with free thyroxine index (r = 0.63–0.74) and with the serum triiodothyronine level (r = 0.83–0.87). The thyroid hormone level was neither correlated with basal rate of lipolysis nor with basal cyclic AMP production (r < 0.2). These results suggest that the magnitude of catecholamine-induced cyclic AMP production by peripheral cells may be regulated by the level of circulating thyroid hormones. The effect of thyroid hormones on lipolysis appears to be specifically linked to the action of catecholamines.

STIMULATION OF PROSTAGLANDIN ACCUMULATION IN THE RAT ANTERIOR PITUITARY GLAND BY LUTEINIZING HORMONE RELEASING HORMONE IN VITRO

1977 ◽  
Vol 75 (2) ◽  
pp. 277-283 ◽  
Author(s):  
N. BARDEN ◽  
A. BETTERIDGE
Keyword(s):  
Luteinizing Hormone ◽  
Cyclic Amp ◽  
Anterior Pituitary ◽  
Pituitary Cells ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Lh Release ◽  
Lh Rh ◽  
Stimulation Of

The addition of luteinizing hormone releasing hormone (LH-RH) to cultures of monolayers of rat anterior pituitary cells was shown to increase both the concentrations of prostaglandins E1 and E2 (PGE) in the cells and the release of LH over similar ranges of concentrations of LH-RH (10−6 to 10−10 mol/l). The peak concentration of PGE was observed after 2·5 h. The stimulation of the level of PGE in the cells by LH-RH was completely inhibited by two inhibitors of prostaglandin synthetase, which only partially inhibited the stimulation of LH release. Therefore the increased concentration of PGE was not obligatory for the effect of LH-RH on LH release. It was also shown that monobutyryl cyclic AMP stimulated the intracellular concentration of PGE and it is suggested that the stimulation of PGE levels may be mediated by increased levels of cyclic AMP in the cells after the addition of LH-RH.

scholarly journals Studies on rat ovarian receptors for lutropin (luteinizing hormone). Interaction with β-subunit of sheep lutropin

1976 ◽  
Vol 160 (3) ◽  
pp. 615-619 ◽  
Author(s):  
K Muralidhar ◽  
N R Moudgal
Keyword(s):  
Biological Activity ◽  
Luteinizing Hormone ◽  
Cyclic Amp ◽  
Chorionic Gonadotropin ◽  
Lower Order ◽  
Ovarian Response ◽  
Β Subunit ◽  
Α Subunit ◽  
Human Choriogonadotropin

By using radioimmunoassay, the interaction of sheep lutropin (luteinizing hormone, LH) β-subunit with rat ovarian receptors was investigated. The binding of β-subunit was specific, although of much lower order than that of lutropin. Sheep lutropin β-subunit effectively inhibited the binding of human choriogonadotropin (chorionic gonadotropin, gCG) to the ovary, showing that both occupy the same sites. The binding of sheep lutropin β-subunit to ovary was not followed by any detectable increase in cyclic AMP. The ovarian response to lutropin in terms of cyclic AMP production was inhibited in the presence of free β-subunit. The α-subunit of lutropin, when used at concentrations where contamination with whole lutropin was negligible, enhanced the degree of binding of β-subunit; this did not lead to increased cyclic AMP in the tissue. Surprisingly, the binding of β-subunit in vitro was drastically decreased by the prior removal of all endogenous rat lutropin bound to receptors. The implications of these data are discussed in the light of the reported biological activity of the β-subunit.

THE IN VITRO EFFECT OF HYPOXIA ON THE TROUT ERYTHROCYTE beta-ADRENERGIC SIGNAL TRANSDUCTION SYSTEM

1993 ◽  
Vol 176 (1) ◽  
pp. 103-116
Author(s):  
S. D. Reid ◽  
Y. Lebras ◽  
S. F. Perry
Keyword(s):  
Signal Transduction ◽  
Cyclic Amp ◽  
Binding Assays ◽  
Signal Transduction System ◽  
Beta Adrenoceptors ◽  
Hypoxic Conditions ◽  
Surface Population ◽  
System 1 ◽  
Vitro Effect

We have investigated the effects of acute in vitro hypoxia on trout (Oncorhynchus mykiss) erythrocytes in order to elucidate the mechanism(s) by which increased catecholamine responsiveness of the Na+/H+ antiporter is achieved. Blood was withdrawn from cannulated trout and maintained in vitro under normoxic (PO2=17.9+/−0.2 kPa, N=12) or hypoxic (PO2=2.8+/−0.1 kPa, N=12) conditions for 30 min prior to exposure to concentrations of noradrenaline, forskolin or 8-bromo-cyclic AMP ranging from 0 to 10–6 mol l-1, 10-7 to 10-5 mol l-1 or 10-4 to 10-2 mol l-1, respectively. Na+/H+ exchange activity was quantified as the maximal reduction in whole-blood pH (pHe) after addition of the various Na+/H+ antiporter activators. Erythrocyte intracellular cyclic AMP contents were also determined after addition of noradrenaline or forskolin. To complete the investigation, radioreceptor binding assays were conducted on separate blood samples to characterize the numbers and affinities of the surface population of beta-adrenoceptors of erythrocytes maintained under normoxic or hypoxic conditions. Exposure of erythrocytes to noradrenaline, forskolin or 8-bromo-cyclic AMP resulted in dose- dependent reductions in pHe as a result of Na+/H+ antiporter activation. In all cases, the effects were significantly more pronounced under hypoxic than normoxic conditions. Hypoxia significantly increased the production of cyclic AMP in the presence of noradrenaline but did not affect the forskolin-induced production of cyclic AMP. Blood oxygen status also affected the number of beta- adrenoceptors expressed at the erythrocyte surface; hypoxic erythrocytes possessed 880.7+/−28.6 (N=6) receptors per cell whereas normoxic erythrocytes possessed 532.6+/−43.2 (N=6) receptors per cell. These results suggest that in vitro exposure of trout erythrocytes to hypoxic conditions results in at least two significant alterations in the catecholamine signal transduction system: (1) an enhancement in erythrocyte cyclic AMP production, in part by virtue of an increase in the number of surface beta- adrenoceptors, and (2) a hypoxia-induced increase in the cyclic AMP sensitivity of one or more of the steps culminating in Na+/H+ antiporter activation. These events ultimately increase the responsiveness of the erythrocyte Na+/H+ antiporter to catecholamines during hypoxia.

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