Effect of progesterone on peripheral blood flow in prepubertal female anesthetized pigs.
This study was undertaken to determine the effects of progesterone on the peripheral circulation. In prepubertal female pigs anesthetized with sodium pentobarbitone, changes in the superior mesenteric, left renal and left external iliac flow caused by intravenous infusion of progesterone were assessed using electromagnetic flow meters. Changes in heart rate and arterial blood pressure were prevented by atrial pacing and by connecting the arterial system to a pressurized reservoir containing Ringer solution. In 20 pigs, infusion of 1 mg/kg of progesterone increased mesenteric, renal and iliac flow. In a further 4 pigs, the vasodilatory effects of the hormone were enhanced by graded increases in the dose between 1, 2 and 3 mg/kg. The mechanisms of these responses were studied in the 20 pigs by repeating the experiment after hemodynamic variables had returned to the control values before infusion. In 5 pigs, blockade of adrenergic receptors with propranolol and phentolamine did not affect the responses elicited by progesterone. The increases in mesenteric, renal and iliac flow to progesterone were prevented, respectively, by the injection of N(omega)-nitro-L-arginine methyl ester into the mesenteric (5 pigs), the renal (5 pigs) or the iliac artery (5 pigs). The present study shows that intravenous infusion of progesterone dilated mesenteric, renal and iliac circulations. The mechanism of this response involved the release of nitric oxide.
Molinari
C
C
Laboratorio di Fisiologia, Dipartimento di Scienze Mediche, Facoltà di Medicina e Chirurgia di Novara, Università del Piemonte Orientale A. Avogadro, Novara, Italy. molinari@med.unipmn.it
Battaglia
A
A
Grossini
E
E
Mary
D A
DA
Surico
N
N
Vacca
G
G
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001775:Blood Circulation / Q000187:drug effects*; D002319:Cardiovascular System / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D007083:Iliac Artery / Q000502:physiology; D007262:Infusions, Intravenous; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D011374:Progesterone / Q000008:administration & dosage / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology; D012039:Regional Blood Flow / Q000187:drug effects; D012079:Renal Circulation / Q000187:drug effects; D013152:Splanchnic Circulation / Q000187:drug effects; D013552:Swine
D000317:Adrenergic alpha-Antagonists; D004791:Enzyme Inhibitors; D011374:Progesterone; D011433:Propranolol; D019331:NG-Nitroarginine Methyl Ester; D010646:Phentolamine