On the synthesis of prostaglandins E1, E2 and E2 alpha by sow oviducts. Differential modulation of 1 and 2 series of prostaglandins by norepinephrine.
The present study was performed in order to evaluate whether norepinephrine (NE) can modulate the synthesis and release of 1 and 2 series of prostaglandins (PGs) by the isthmic region of preovulatory sow oviducts and also to clarify whether the action of the neurotransmitter is mediated through alpha, through beta or through both types of tissue adrenoreceptors. NE, at a concentration of 1 microgram/ml, depressed significantly (P less than 0.05) the basal output of PGE1 and enhanced (P less than 0.01) the release of PGE2 but, did not modify, the output of "PGF2 alpha-like material". Propranolol (10(-7)M) failed to alter the basal output of "PGE1, PGE2 or PGF2 alpha-like material". In the presence of this beta-adrenoreceptor blocker, the depression induced by NE on PGE1 output, was abolished; its stimulatory influence on the release of PGE2, was eliminated and no effect was detected regarding PGF2 alpha. On the other hand, phentolamine (10(-6)M) did not alter the basal output of "PGE1, PGE2 or PGF2 alpha-like material" and also failed to modify the depression induced by NE on PGE1 release. However, this alpha adrenoceptor blocker completely inhibited the stimulatory action of NE on the output of PGE2 into the incubating medium. The foregoing results document opposite actions of NE on PGE1 and PGE2 outputs from the isthmic region of proestrous sow oviducts and suggest the involvement of beta-adrenoreceptors in both disparate influences. The activation of alpha adrenoreceptors also appears associated with the enhancing effect of the agonist on the release of PGE2. The possible physiological significance of these findings is discussed in terms of the function of the isthmic region as an "adrenergic sphincter" able to influence ovum transport around the moment of ovulation.
Gimeno
M F
MF
Franchi
A M
AM
Faletti
A
A
Gonzalez
E T
ET
Gimeno
A L
AL
D000527:Alprostadil; D000818:Animals; D015237:Dinoprost; D015232:Dinoprostone; D005187:Fallopian Tubes / Q000378:metabolism*; D005260:Female; D009638:Norepinephrine / Q000494:pharmacology*; D010646:Phentolamine / Q000494:pharmacology; D011247:Pregnancy; D011359:Proestrus; D011433:Propranolol / Q000494:pharmacology; D011458:Prostaglandins E / Q000096:biosynthesis*; D011460:Prostaglandins F / Q000096:biosynthesis*; D011942:Receptors, Adrenergic, alpha / Q000502:physiology; D011943:Receptors, Adrenergic, beta / Q000502:physiology; D013552:Swine
D011458:Prostaglandins E; D011460:Prostaglandins F; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D011433:Propranolol; D015237:Dinoprost; D000527:Alprostadil; D015232:Dinoprostone; D009638:Norepinephrine; D010646:Phentolamine