EFFECT OF HUMAN CHORIONIC GONADOTROPHIN ON ADENYLATE CYCLASE ACTIVITY AND TESTOSTERONE CONTENT IN RAT TESTICULAR MITOCHONDRIA

1977 ◽  
Vol 75 (1) ◽  
pp. 119-126 ◽  
Author(s):  
SOREL SULIMOVICI ◽  
M. S. ROGINSKY
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Dibutyryl Cyclic Amp ◽  
Trophic Hormone

The adenylate cyclase activity and the concentration of testosterone in testicular mitochondria from immature rats were measured after administration of human chorionic gonadotrophin (HCG) or dibutyryl cyclic AMP in vivo or in vitro. Intratesticular injection of HCG produced an increase in adenylate cyclase activity which preceded the rise in the level of testosterone, whereas addition of the trophic hormone in vitro resulted in simultaneous increases. Administration of dibutyryl cyclic AMP in vivo enhanced the testosterone content of the mitochondria. However, the cyclic nucleotide added in vitro at concentrations up to 5 mmol/l had no effect. Cycloheximide injected intraperitoneally before the administration of HCG abolished the stimulatory effect of the trophic hormone on the level of testosterone in the mitochondria, whereas chloramphenicol had no effect. These results, although they confirm the role of cyclic AMP as an intermediate in the stimulatory effect of HCG on the concentration of testosterone in rat testis, do not support a role for mitochondrial adenylate cyclase in this action. A protein regulator(s) formed extramitochondrially appears to be involved in the stimulatory effect of gonadotrophins on steroidogenesis.

Cytochemical Evidence for Presynatic β-Adrenergic Regulation of Secretion in the Developing Rat Submandibular Gland

1977 ◽  
Vol 35 ◽  
pp. 430-431
Author(s):  
L.S. Cutler
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Submandibular Gland ◽  
Neonatal Rat ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Parotid Glands ◽  
Adrenergic Agonist ◽  
Rat Submandibular Gland

Many studies previously have shown that the B-adrenergic agonist isoproterenol and the a-adrenergic agonist norepinephrine will stimulate secretion by the adult rat submandibular (SMG) and parotid glands. Recent data from several laboratories indicates that adrenergic agonists bind to specific receptors on the secretory cell surface and stimulate membrane associated adenylate cyclase activity which generates cyclic AMP. The production of cyclic AMP apparently initiates a cascade of events which culminates in exocytosis. During recent studies in our laboratory it was observed that the adenylate cyclase activity in plasma membrane fractions derived from the prenatal and early neonatal rat submandibular gland was retractile to stimulation by isoproterenol but was stimulated by norepinephrine. In addition, in vitro secretion studies indicated that these prenatal and neonatal glands would not secrete peroxidase in response to isoproterenol but would secrete in response to norepinephrine. In contrast to these in vitro observations, it has been shown that the injection of isoproterenol into the living newborn rat results in secretion of peroxidase by the SMG (1).

Protease effects on adenylate cyclase in potassium-depleted rabbit kidney

1988 ◽  
Vol 255 (5) ◽  
pp. F1033-F1039
Author(s):  
K. H. Raymond ◽  
S. D. Holland ◽  
T. K. Hymer ◽  
T. D. McKinney ◽  
M. S. Katz
Keyword(s):  
Adenylate Cyclase ◽  
Proteolytic Enzymes ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Rabbit Kidney ◽  
Potassium Depletion ◽  
Collecting Tubules ◽  
And Control

Potassium depletion in rabbits induces a renal concentrating defect in vivo and decreased hydrosmotic response to arginine vasopressin (AVP) in isolated cortical collecting tubules (CCT) perfused in vitro. The molecular basis of the AVP resistance in potassium depletion was investigated by comparing AVP-responsive adenylate cyclase activities in CCT from potassium-depleted and control rabbits. Vasopressin-responsive enzyme activity was impaired in CCT dissected from kidneys of potassium-depleted rabbits but not when kidneys were treated with collagenase to improve microdissection conditions. Potassium depletion also depressed parathyroid hormone (PTH)-stimulated adenylate cyclase activity in proximal straight tubules (PST) dissected from untreated but not collagenase-treated kidneys. Commercially available collagenase, which also contains other proteolytic enzymes, increased AVP-sensitive adenylate cyclase activity in control CCT, and trypsin treatment of CCT dissected without collagenase abolished the decrease in AVP-sensitive activity induced by potassium depletion. Inclusion of trypsin inhibitor during collagenase treatment of kidneys lowered AVP response in CCT from potassium-depleted rabbits. These results demonstrate that potassium depletion impairs hormone-sensitive adenylate cyclase of CCT (and PST) by a protease-sensitive mechanism.

Characterization of a factor(s) from partially purified human gonadotrophin preparations which inhibit(s) the binding of radiolabelled human LH and human chorionic gonadotrophin to Candida albicans

1991 ◽  
Vol 128 (1) ◽  
pp. 139-151 ◽  
Author(s):  
T. A. Bramley ◽  
G. S. Menzies ◽  
R. J. Williams ◽  
O. S. Kinsman ◽  
D. J. Adams
Keyword(s):  
Candida Albicans ◽  
Adenylate Cyclase ◽  
Core Protein ◽  
Proteolytic Enzymes ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Partial Purification ◽  
Core Proteins

ABSTRACT We have shown previously that partially purified human chorionic gonadotrophin (hCG) preparations inhibited the specific binding of I-labelled hLH or hCG to Candida albicans membranes at much lower concentrations than did highly purified hLH or hCG preparations. We now describe the characterization and partial purification of a heat-labile glycoprotein from commercially available gonadotrophin preparations. The factor strongly inhibited LH binding to Candida membranes, but not to sheep or pig luteal LH receptors. This material had a molecular weight of 16 000–21 000 daltons, bound strongly to CM-Sepharose at physiological pH, and could be resolved completely from hCG and from epidermal growth factor-like factors present in commercial gonadotrophin preparations. Its activity was not attenuated by a range of inhibitors specific for the four major classes of proteolytic enzymes, nor did it inhibit hormone binding by causing degradation of 125 I-labelled hLH or hCG tracers. Factors which inhibited hLH binding to Candida membranes were also present in partially purified human urinary and equine serum gonadotrophin preparations and in placental extracts, but were not detected in highly purified CG of hLH preparations. The properties of this factor were similar to those described for β-core protein, a cleavage product of the β subunit of hCG which is a contaminant of commercial gonadotrophin preparations. Highly purified β-core protein inhibited 125I-labelled hLH binding to Candida membranes, but not to sheep luteal binding sites. Preparations of hCG depleted of inhibitor activity could stimulate adenylate cyclase activity in Candida membranes almost five fold. In contrast, partially purified inhibitor preparations strongly inhibited basal adenylate cyclase activity (to 18% of control levels). These observations suggest that endogenous LH-like factors, perhaps similar to β-core proteins of hCG, may play a role in the regulation of morphogenesis in Candida species. Journal of Endocrinology (1991) 128, 139–151

Antisecretory effects of berberine in rat ileum

1981 ◽  
Vol 241 (3) ◽  
pp. G253-G258 ◽  
Author(s):  
Y. H. Tai ◽  
J. F. Feser ◽  
W. G. Marnane ◽  
J. F. Desjeux
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Rat Ileum ◽  
Ion Secretion ◽  
Stimulation Of

The in vitro antisecretory effects of the alkaloid berberine (1.0 mM) on intestinal ion secretion and mucosal adenylate cyclase and Na-K-ATPase activities were studied in the rat ileum. Mucosal berberine did not alter the individual basal net ion fluxes and basal adenylate cyclase activity but decreased short-circuit current (Isc) and increased the net absorption of chloride plus bicarbonate. In the cholera toxin-treated tissue, mucosal berberine stimulated absorption of Na and Cl and inhibited the increased adenylate cyclase activity but did not change the specific Na-K-ATPase activity, whereas serosal berberine stimulated Na secretion and decreased Isc. Mucosal berberine also decreased Isc, increased Cl permeability, and reversed the ion secretion induced by dibutyryl cyclic AMP, the heat-stable enterotoxin of Escherichia coli, and methylprednisolone administration. The antisecretory effects of mucosal berberine may be explained by stimulation of a Na-Cl-coupled absorptive transport process. The mechanism of action of serosal berberine remains to be elucidated. However, it is clear that mucosal berberine affects intestinal ion transport by mechanisms different from stimulation of the Na pump and probably at a step distal to the production or degradation of cyclic AMP or cyclic GMP.

EFFECT OF LUTEINIZING HORMONE ON THE CONCENTRATION OF CYCLIC GMP IN RABBIT OVARIES

1978 ◽  
Vol 79 (2) ◽  
pp. 251-252
Author(s):  
V. V. PATWARDHAN ◽  
A. LANTHIER
Keyword(s):  
Luteinizing Hormone ◽  
Cyclic Amp ◽  
Cyclic Gmp ◽  
Ovarian Tissue ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Direction Opposite ◽  
Stimulation Of

Laboratoire d'Endocrinologie, Hôpital Notre-Dame et Département de Medicine, Université de Montréal, Montréal, Canada (Received 28 June 1978) Cyclic AMP has been implicated as an intermediate in some of the actions of luteinizing hormone (LH) on ovarian tissues, such as stimulation of steroidogenesis (LeMaire & Marsh, 1975). Both in vitro (Marsh, Butcher, Savard & Sutherland, 1966) and in vivo (Armstrong, Dorrington & Robinson, 1976), stimulation with LH results in a rapid increase in the amount of cyclic AMP in ovarian tissues, which precedes the LH-induced increase in steroidogenesis. Recently, studies on rat ovaries (Grinwich, Ham, Hichens & Behrman, 1976; Ratner, 1976; Ratner & Sanborn, 1976) have indicated that the ovarian tissue content of cyclic GMP may also be regulated by LH, but in a direction opposite to that of cyclic AMP. In the rabbit, Goff & Major (1975) have shown that administration of human chorionic gonadotrophin (HCG) causes a biphasic increase

Decrease in adenylate cyclase activity in dog livers during endotoxic shock

1983 ◽  
Vol 245 (5) ◽  
pp. R737-R742
Author(s):  
S. Ghosh ◽  
M. S. Liu
Keyword(s):  
Adenylate Cyclase ◽  
Plasma Membranes ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Guanine Nucleotide ◽  
Endotoxin Administration ◽  
Liver Plasma Membranes ◽  
Dog Liver

The effects of endotoxin administration on adenylate cyclase in dog liver plasma membranes were studied. The basal, fluoride-, guanine nucleotide-, isoproterenol-, and glucagon-stimulated adenylate cyclase activities were decreased by 61, 62, 69, 83, and 63%, respectively, 2 h after in vivo administration of endotoxin. Endotoxin (100 micrograms/ml) in vitro decreased the guanine nucleotide-, isoproterenol-, and glucagon-stimulated adenylate cyclase activities by 24, 25, and 21%, respectively. These data demonstrate that endotoxin administered in vivo or in vitro had an inhibitory effect on the adenylate cyclase enzyme system in dog liver plasma membranes. Because of the involvement of the adenylate cyclase-adenosine 3',5'-cyclic monophosphate (cAMP) system in the regulation of hepatic carbohydrate metabolism, the finding that endotoxin administration decreased adenylate cyclase activity in the liver should contribute to the understanding of the pathophysiology of altered hepatic glucose homeostasis during shock.

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