Reduced oxygen consumption of brown adipocytes isolated from progesterone-treated rats.
It has been previously shown that responsiveness to noradrenaline is reduced in brown adipocytes isolated from estradiol-treated rats. The possibility that high plasma levels of progesterone could also alter adrenergic response was checked. The oxygen consumption of brown adipocytes isolated from control and progesterone-treated rats was monitored in basal conditions and in the presence of increasing concentrations of noradrenaline. In both situations, cells isolated from treated animals showed a lower respiratory rate than those from control animals. These results suggest that not only estradiol but also progesterone could modulate the adrenergic response of brown adipocytes. The study of alpha 1- and beta-adrenergic responses indicates that the beta-response parallels the general reduction in oxygen consumption, although the alpha 1-response seems to be more deeply depressed. Estimation of cell number in brown fat depots indicates some hyperplasia induced by progesterone; this increase in cell number could counterbalance partially but not totally the decreased cellular oxygen consumption at the organ level.
Abelenda
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M
Department of Animal Biology II (Animal Physiology), Faculty of Biological Sciences, Complutense University, Madrid, Spain.
Castro
C
C
Venero
C
C
Puerta
M
M
D017667:Adipocytes / Q000187:drug effects; D002001:Adipose Tissue, Brown / Q000187:drug effects* / Q000473:pathology; D000818:Animals; D004305:Dose-Response Relationship, Drug; D003576:Electron Transport Complex IV / Q000032:analysis; D005260:Female; D006965:Hyperplasia; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology*; D010101:Oxygen Consumption / Q000187:drug effects*; D010656:Phenylephrine / Q000494:pharmacology; D011374:Progesterone / Q000008:administration & dosage / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology; D051381:Rats
D010656:Phenylephrine; D011374:Progesterone; D011433:Propranolol; D003576:Electron Transport Complex IV; D007545:Isoproterenol; D009638:Norepinephrine