Effects of different opiate agonists on melanocyte-stimulating hormone release: in vivo and in vitro studies

1980 ◽  
Vol 58 (3) ◽  
pp. 326-329 ◽  
Author(s):  
M. E. Celis
Keyword(s):  
Opioid Peptides ◽  
In Vitro Studies ◽  
Hormone Release ◽  
Low Concentration ◽  
Melanocyte Stimulating Hormone ◽  
Dose Dependent ◽  
Stimulating Hormone

The effects of Leu-enkephalin, Met-enkephalin, and β-endorphin on melanocyte-stimulating hormone (MSH) secretion were studied in vivo and in vitro. The three opioid peptides release MSH. In vitro this release is dose dependent for Met-enkephalin between 10 and 1000 ng/mL and for Leu-enkephalin between 10 and 100 ng/mL. β-Endorphin releases MSH at the low concentration of 1 ng/mL and the effect is dose dependent between 1 and 100 ng/mL. Naloxone reverses this effect. In vivo the three petptides release MSH.

Influence of SIN-1 on Platelet Ca2+ Handling in Patients with Suspected Coronary Artery Disease: Ex Vivo and In Vitro Studies

2000 ◽  
Vol 83 (05) ◽  
pp. 752-758 ◽  
Author(s):  
Claude Le Feuvre ◽  
Annie Brunet ◽  
Thuc Do Pham ◽  
Jean-Philippe Metzger ◽  
André Vacheron ◽  
...  
Keyword(s):  
Superoxide Anion ◽  
Vascular Tone ◽  
Ex Vivo ◽  
Suspected Coronary Artery Disease ◽  
In Vitro Studies ◽  
H2o2 Formation ◽  
Artery Disease ◽  
Dose Dependent

SummaryThe 3-morpholinosydnonimine (SIN-1) generates both nitric oxide (NO) and superoxide anion (O2−). It elicits dose-dependent vasodilation in vivo, in spite of the opposite effects of its breakdown products on vascular tone and platelet aggregation.This study was designed to investigate the influence of intravenous SIN-1 injection on platelet Ca2+ handling in patients undergoing coronary angiography. SIN-1 administration reduced cytosolic [Ca2+] in unstimulated platelets by decreasing Ca2+ influx. It attenuated Ca2+ mobilization from internal stores evoked by thrombin or thapsigargin. In vitro studies were used as an approach to investigate how simultaneous productions of NO and O2− from SIN-1 modify thrombin- or thapsigargin-induced platelet Ca2+ mobilization. Superoxide dismutase, the O2− scavenger, enhanced the capacity of SIN-1 to inhibit Ca2+ mobilization but catalase had no effect.This suggests that the effects of SIN-1 on platelet Ca2+ handling resemble those of NO, but are modulated by simultaneous O2− release, independently of H2O2 formation.

scholarly journals Inhibin B Is a More Potent Suppressor of Rat Follicle-Stimulating Hormone Release than Inhibin A in Vitro and in Vivo

Endocrinology ◽  
2009 ◽  
Vol 150 (10) ◽  
pp. 4784-4793 ◽  
Author(s):  
Yogeshwar Makanji ◽  
Peter D. Temple-Smith ◽  
Kelly L. Walton ◽  
Craig A. Harrison ◽  
David M. Robertson
Keyword(s):  
Follicle Stimulating Hormone ◽  
Inhibin B ◽  
Hormone Release ◽  
Inhibin A ◽  
Stimulating Hormone

Three types of alpha-melanocyte-stimulating hormone: bioactivities and half-lives

1983 ◽  
Vol 245 (1) ◽  
pp. E47-E54 ◽  
Author(s):  
D. Rudman ◽  
B. M. Hollins ◽  
M. H. Kutner ◽  
S. D. Moffitt ◽  
M. J. Lynn
Keyword(s):  
Tissue Slices ◽  
Melanocyte Stimulating Hormone ◽  
Lipolytic Action ◽  
Acetyl Group ◽  
Isolated Adipocytes ◽  
Hydroxy Groups ◽  
Kinetics Of ◽  
Stimulating Hormone

Three types of alpha-melanocyte-stimulating hormone (alpha MSH) that differ in the acetyl status of the N-terminal serine have been found in the neurointermediate lobe of the pituitary gland and in the brain: desacetyl alpha MSH, which lacks an acetyl group; monoacetyl alpha MSH, in which the amino group of the serine is acetylated; and diacetyl alpha MSH, in which both amino and hydroxy groups of the serine are acetylated. We compared the lipolytic and melanotropic actions of these three peptides, and their rates of disappearance from plasma, both in vitro and in vivo. The following differences were found. a) For in vitro lipolytic actions on rabbit adipose tissue slices, the potencies differed according to the order diacetyl = monoacetyl greater than desacetyl. On rabbit isolated adipocytes, however, the three peptides were equipotent. b) For in vivo lipolytic action in the rabbit, not only potency but also kinetics differed. Diacetyl alpha MSH had the slowest onset, longest duration, and greatest potency. The desacetyl variant had the quickest onset, shortest duration, and least potency. c) The half-life for elimination from rabbit plasma both in vitro and in vivo was shortest for the desacetyl form and longest for the diacetyl peptide. d) For in vitro melanotropic effect on frog skin, kinetics of action were the same for all three peptides, but potency differed according to the order diacetyl = monoacetyl greater than desacetyl. Thus acetylation of alpha MSH alters lipolytic and melanotropic potencies in vitro and lipolytic potency and kinetics in vivo. These differences result in part from the fact that acetylation slows the degradation of the tridecapeptide both inside and outside the circulation.

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