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Query: UNIPROT:P01185 (
vasopressin
)
23,126
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The antidiuretic action of a number of
vasopressin
analogues has been measured in the rat and man in water diuresis. These analogues had the following categories of structural alteration: a) substitution of -CH2CH2-(dicarba) and -SCH2-(6-monocarba) for the natural -SS- bridge between residues 1 and 6, b) changes in the nature of the C-terminal tripeptide produced by substitution of D-arginine and L-Nalpha-methylarginine for L-arginine in sequence position 8 and
L-leucine
for proline in position 7, and c) combinations of a and b. In addition, a highly active analogue which results when valine is substituted for glutamine in position 4 was tested. Trained, unanesthetized rats and normal human volunteers were complemented by a volunteer patient with posttraumatic diabetes insipidus (DI) in the total group of experimental subjects. The only change in the C-terminal tripeptide which was associated with a high antidiuretic action was D-Arg substitution. The meArg and Leu analogues showed low to very little activity and no signs of antidiuretic antagonist action. All of the carba analogues showed both high potency and prolongation of antidiuretic action in the following order (for both potency and duration): monocarba + 8-D-Arg greater than 4-Val + 8-D-Arg greater than 8-D-Arg alone, all in deamino form. None of the 8-D-Arg analogues had any side effects on the cardiovascular system, gut, uterus, bladder, etc. The prolongation was such that even with a DI patient refractory to the action of lysine-
vasopressin
and relatively resistant to deamino-[8-D-Arg]-
vasopressin
, water turnover could be reduced from untreated levels of 20 to 30 liters/day to less than 2 liters/day with only a single administration of deamino-6-carba-[8-D-Arg]-
vasopressin
as nose drops. The significance of these structural alterations in the
vasopressin
molecule for interaction with both antidiuretic and smooth muscle receptors was discussed.
...
PMID:Role of the disulfide bridge and the C-terminal tripeptide in the antidiuretic action of vasopressin in man and the rat. 119 61
The transport of
L-leucine
across the blood-brain barrier was studied in heterozygous (NON-DI) and homozygous (DI) Brattleboro male rats using the carotid bolus injection technique. Furthermore, general hemodynamic parameters and cerebral blood flow were measured. No significant hemodynamic differences were found between DI and NON-DI rats except for a 22% lower cerebral blood flow in the olfactory bulb of DI rats. The maximum velocity of
L-leucine
transport (Vmax), the half saturation constant (Km) and the nonsaturable transport constant (KD) were estimated in nine brain regions. The Vmax values of NON-DI rats were by 28% to 64% lower than those of DI rats. The calculated regional Km values of NON-Di rats were by 14% to 58% lower. These differences were most pronounced in hippocampus and hypothalamus. The results support the suggestion that endogenous
vasopressin
may alter the large neutral amino acid transport across the blood-brain barrier.
...
PMID:Kinetics of regional blood-brain barrier transport of L-leucine in Brattleboro rats. 325 49
Arginine-
vasopressin
(AVP), injected into the carotid artery in physiological concentration together with
L-leucine
, changed kinetic constants of the blood-brain barrier (BBB) transport of this neutral amino acid without changing the cerebral blood flow (CBF). The maximum velocity of transport (Vmax), the half-saturation constant (Km), the nonsaturable transport constant (KD), and CBF were estimated in nine brain regions of male Wistar rats anesthetized with ether. In cerebral hemisphere, Vmax decreased from 21 nmol . min-1 . g-1 (control) to 7.6 nmol . min-1 . g-1 (AVP). Km decreased from 0.11 to 0.029 mM. Regional differences of the kinetic constants were found in controls as well as in AVP-treated animals. In all regions, the calculated constants Vmax and Km of animals coinjected with AVP were significantly decreased when compared to controls. A direct or indirect interaction of AVP with the transport system of large neutral amino acids is suggested.
...
PMID:Changes in regional blood-brain transfer of L-leucine elicited by arginine-vasopressin. 394 19
Aminopeptidase from dysgerminoma was purified and characterized using
L-leucine
-beta-naphthylamide as substrate. The enzyme was resistant to puromycin, methionine, amastatin, bastatin, and EDTA, and it was heat labile at 60 degrees C. The enzyme showed the same electrophoretic mobility as pregnant-patient serum oxytocinase CAP1 on polyacrylamide gel electrophoresis. Km value against S-benzylcysteine-p-nitroanilide was 4.2 X 10(-4) M. Oxytocin and
vasopressin
competitively inhibited the enzyme activity. Molecular weight of the enzyme was estimated to be 80,000 by Sephadex G-200 column chromatography. These results suggest that aminopeptidase from dysgerminoma is an oxytocinase-like enzyme, a placenta-specific protein.
...
PMID:Oxytocinase-like enzyme in an ovarian dysgerminoma: a placenta-specific protein. 408 42
Angiotensin II (AII), an important hypertrophic factor in the cardiovascular system, exerts most of its known effects in vivo through the AII receptor type 1 (AT1) subclass of AII receptors. These receptors are also responsible for the growth-related effects of AII in cultured vascular smooth muscle cells (VSMCs). We presently investigated the effects of BAY 10-6734 (Embusartan), a new orally active AT1 antagonist, on VSMC growth and proliferation of cultured VSMCs isolated from the aortae of Wistar Kyoto rats and spontaneously hypertensive rats. BAY 10-6734 and losartan (considered as AT1 receptor antagonist of reference), as well as their respective active metabolites, were studied for their inhibition of: 1) [125I]AII binding to its receptors, 2) AII-induced DNA and protein synthesis (by measuring the incorporation of 5-bromo-2'-deoxyuridine and [3H]
L-leucine
, respectively), and 3) AII-induced variations in intracellular Ca2+ concentration, using cells labeled with Fura-2. All of the tested compounds inhibited the aforementioned parameters in a concentration-dependent manner. Half-maximal inhibitory concentration values indicated that BAY 10-6734 was significantly more potent than losartan and that spontaneously hypertensive rat-derived VSMCs were more sensitive than Wistar Kyoto rat-derived ones. Neither BAY 10-6734 nor losartan affected the intracellular Ca2+ concentration of unstimulated VSMCs but both compounds inhibited both AII-induced Ca2+ mobilization from internal stores and Ca2+ influx. Neither compound affected
arginine-vasopressin
-, basic fibroblast growth factor-, or serum-induced DNA and protein synthesis. BAY 10-6734 appears therefore as a potent and specific new inhibitor of AII-induced growth-related events in VSMCs.
...
PMID:Effects of BAY 10-6734 (Embusartan), a new angiotensin II type I receptor antagonist, on vascular smooth muscle cell growth. 1008 2