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Suppression of luteinizing hormone release by the α 1 ‐adrenergic receptor antagonist prazosin in the ovariectomized female rhesus monkey
Author(s) -
Gearing Marla,
Terasawa Ei
Publication year - 1991
Publication title -
american journal of primatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.988
H-Index - 81
eISSN - 1098-2345
pISSN - 0275-2565
DOI - 10.1002/ajp.1350250103
Subject(s) - prazosin , endocrinology , medicine , ovariectomized rat , antagonist , adrenergic antagonist , rauwolscine , luteinizing hormone , chemistry , receptor , hormone
The effects of adrenergic antagonists on LH release were examined in ovariectomized female rhesus monkeys implanted with indwelling jugular catheters. While the α 2 ‐adrenergic antagonist rauwolscine and the vehicle were without effect, the α 1 ‐antagonist prazosin suppressed LH release. In 5 of the 8 monkeys tested, LH pulses were completely arrested; in the remaining 3 monkeys, small LH pulses were detectable after the administration of 0.2 mg/kg prazosin. In a second series of experiments, the effects of three different doses of prazosin were examined. Doses of 0.1 mg/kg and 0.4 mg/kg suppressed LH release in a manner indistinguishable from that of the 0.2 mg/kg dose. Finally, the ability of the pituitary to respond to a bolus of LHRH during the prazosin‐induced suppression was tested. In all 6 animals, the injection of LHRH during the time when LH was suppressed by prazosin resulted in a marked increase in LH release. These results indicate 1) that α 1 ‐adrenergic receptors but not α 2 receptors are important for pulsatile LH secretion, 2) that varying the dose of prazosin administered does not alter the effect of the drug or LH release within the range of doses tested, and 3) the pituitary is able to respond to LHRH with an increase in LH release during the prazosin‐induced suppression period.