The preparation and metabolic fate of tritiated Nα-acetyl[2-O-methyltyrosine]oxytocin - An inhibitor of the uterotonic action of oxytocin

1979 ◽  
Vol 44 (9) ◽  
pp. 2702-2709
Author(s):  
Vera Bojanovska ◽  
Tomislav Barth ◽  
Bohuslav Černý ◽  
Karel Hauzer ◽  
Karel Jošt
Keyword(s):  
Biological Activity ◽  
Mammary Gland ◽  
Specific Radioactivity ◽  
Subcellular Fractions ◽  
Metabolic Fate ◽  
Rat Uterus ◽  
Peptide Bonds ◽  
Human Pregnancy ◽  
Metabolic Products

An inhibitor of the uterotonic action of oxytocin-[CH3CO-3H] [2-O-methyltyrosine]oxytocin - having biological activity and a specific radioactivity of 3-7 Ci/mmol was prepared by the reaction of [2-O-methyltyrosine]oxytocin with 2,2'-3H2-acetanhydride. The analogue was stable in human pregnancy serum. Chymotrypsin split the Tyr(Me)-Ile and Leu-GlyNH2 peptide bonds. In the presence of subcellular fractions of homogenates of the rat uterus and mammary gland, several metabolic products were formed from the analogue.

scholarly journals Oestradiol inhibits collagen breakdown in the involuting rat uterus

1972 ◽  
Vol 127 (4) ◽  
pp. 705-713 ◽  
Author(s):  
Janet N. Ryan ◽  
J. Frederick Woessner
Keyword(s):  
Cathepsin D ◽  
Density Gradient Centrifugation ◽  
Post Partum ◽  
Gradient Centrifugation ◽  
Specific Radioactivity ◽  
Rat Uterus ◽  
Oestradiol Treatment ◽  
Cathepsin D Activity ◽  
Stimulation Of

1. The earlier observation (Woessner, 1969) of oestradiol inhibition of collagen breakdown is confirmed and extended. Administration of 100μg of oestradiol-17β/day to parturient rats strongly inhibits the loss of collagen from the involuting uterus. Three experiments show that this effect is due to an inhibition of collagen degradation rather than to a stimulation of collagen synthesis. 2. Uterine collagen was labelled with hydroxy[14C]-proline by the administration of [14C]proline near the end of pregnancy. By 3 days post partum, control uteri lost 83% of their collagen and 90% of their hydroxy[14C]proline. Uteri from oestradiol-treated rats lost only 50% of both total and labelled hydroxyproline, with no decrease in the specific radioactivity of the hydroxyproline. 3. Incorporation of [14C]proline into uterine collagen hydroxyproline in vivo was not affected by oestradiol treatment. 4. Urinary excretion of hydroxyproline was increased in post-partum control rats and decreased in oestradiol-treated rats. 5. An enzyme capable of cleaving 4-phenylazobenzyloxycarbonyl-l-prolyl-l-leucylglycyl- l-prolyl-d-arginine (a substrate for clostridial collagenase) increased in activity in the post-partum uterus and was unaffected by oestradiol treatment. 6. Uterine homogenates digested uterine collagen extensively at pH3.2. This digestion was unaffected by the oestradiol treatment. 7. Lysosomal fractions prepared by density-gradient centrifugation of uterine homogenates contained coincident peaks of cathepsin D activity and peptide-bound hydroxyproline. The cathepsin D and hydroxyproline contents of this peak were unaffected by oestradiol treatment.

METABOLISM OF 20β-HYDROXY-4-PREGNEN-3-ONE IN UTERINE TISSUE OF NON-PREGNANT RATS IN VITRO

1976 ◽  
Vol 83 (3) ◽  
pp. 604-620 ◽  
Author(s):  
B. P. Lisboa ◽  
M. Holtermann
Keyword(s):  
Biological Activity ◽  
Adult Female ◽  
Female Rats ◽  
Uterine Tissue ◽  
Rat Uterus ◽  
Adult Rats ◽  
Pregnant Rats ◽  
Progesterone Metabolites ◽  
Ovariectomized Adult Rats

ABSTRACT In vitro experiments carried out with uterus preparations of ovariectomized adult rats indicate the presence in this tissue of a 20β-hydroxysteroid-oxidoreductase which catalyzes the conversion of 20β-hydroxy-4-pregnen-3-one to progesterone. Since a hepatic 20β-hydroxysteroid-oxidoreductase is absent in adult female rats, the myometrial enzyme can be responsible for the biological activity of 20β-hydroxy-4-pregnen-3-one in these animals. Besides progesterone five metabolites were isolated and identified after incubation of [4-14C]20β-hydroxy-4-pregnen-3-one with uterine tissue: 20β-hydroxy-5α-pregnan-3-one, 20β-hydroxy-5β-pregnan-3-one, 5α-pregnane-3α,20β-diol, 4-pregnene-3α,20β-diol and 4-pregnene-3β,20β-diol. The conversion of 20β-hydroxy-4-pregnen-3-one to progesterone permits us to regard all five steroids isolated as progesterone metabolites in the rat uterus. 20β-hydroxy-5β-pregnan-3-one is the first C21-metabolite with a 5β(H)-configuration isolated in the rat uterus, which indicates the presence of 5β-reductase in this tissue.

METABOLISM IN VITRO OF TRITIATED ADRENOCORTICOTROPIC HORMONE

1965 ◽  
Vol 43 (9) ◽  
pp. 1489-1498 ◽  
Author(s):  
Edward E. Nishizawa ◽  
R. B. Billiar ◽  
J. Karr ◽  
Kristen B. Eik-Nes
Keyword(s):  
Biological Activity ◽  
Adrenal Gland ◽  
Adrenal Cortex ◽  
Enzymatic Degradation ◽  
Adrenocorticotropic Hormone ◽  
Specific Radioactivity ◽  
Adrenocorticotrophic Hormone ◽  
Serine Residue

Adrenocorticotrophic hormone (ACTH) labeled with tritium has been prepared with a specific radioactivity of approximately 4000 d.p.m./μg. The tritiated trophin showed biological activity and appeared to be bound to the cells of the adrenal gland. Data indicating that the adrenal cortex can inactivate ACTH were obtained; whether such inactivation is due to binding or enzymatic degradation has not been illustrated. Attempts to demonstrate that the adrenal gland could acetylate the N-terminal serine residue of ACTH failed.

Metabolic fate of nociceptin/orphanin FQ in the rat spinal cord and biological activity of its released fragment

Peptides ◽  
1999 ◽  
Vol 20 (2) ◽  
pp. 239-247 ◽  
Author(s):  
P. Suder ◽  
J. Kotlinska ◽  
M.T. Smoluch ◽  
M. Sällberg ◽  
J. Silberring
Keyword(s):  
Spinal Cord ◽  
Biological Activity ◽  
Orphanin Fq ◽  
Metabolic Fate ◽  
Rat Spinal Cord

Synthesis and Biological Activity of Four Vasopressin Analogs Modified in Position 3 with β-Thienylalanine

1995 ◽  
Vol 60 (4) ◽  
pp. 681-686 ◽  
Author(s):  
Jiřina Slaninová ◽  
Malgorzata Czaja ◽  
Bernard Lammek
Keyword(s):  
Biological Activity ◽  
Arginine Vasopressin ◽  
Peptide Bonds

Four new analogs of arginine-vasopressin substituted in position 3 with β-thienylalanine were synthesized on chloromethylated resin using Boc strategy and DCC or DCC-HOBt to form peptide bonds. The activity of the agonists is not much different in comparison to the unsubstituted compounds. However, the potency of one of the antagonists is strongly reduced.

Differential regulation of TGF-β2 by hormones in rat uterus and mammary gland

1996 ◽  
Vol 32 (2) ◽  
pp. 125-144 ◽  
Author(s):  
Sara L. Schneider ◽  
Sandra O. Gollnick ◽  
Catherine Grande ◽  
James E. Pazik ◽  
Thomas B. Tomasi
Keyword(s):  
Mammary Gland ◽  
Differential Regulation ◽  
Rat Uterus

Action of [1,6-Di-alanine]-oxytocin and [1,6-Di-serine]-oxytocin on the rat uterus and mammary gland in vitro

1970 ◽  
Vol 9 (2) ◽  
pp. 239-245 ◽  
Author(s):  
Ivo Poláček ◽  
Ivan Krejčí ◽  
Hans Nesvadba ◽  
Josef Rudinger
Keyword(s):  
Mammary Gland ◽  
Rat Uterus
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