title: Testosterone administration to ovariectomized female rhesus monkeys (Macaca mulatta) reduces the frequency of pulsatile luteinizing hormone secretion.
abstract: In the male rhesus monkey testosterone (T) retards the frequency of intermittent LH secretion. The purpose of the present study was to determine whether this action of T is demonstrable in the female. Five ovariectomized rhesus monkeys, bearing indwelling cardiac catheters, were implanted s.c. on one or more occasions with T-containing Silastic capsules. Sequential blood samples were collected for 8 h every 10 min before T treatment and usually at 1, 2, 4, and 8 days thereafter. Plasma LH concentrations were measured in duplicate by radioimmunoassay and subsequently analyzed with a computerized algorithm. Sustained increments in circulating T (5-13 ng/ml) in ovariectomized monkeys resulted in a progressive reduction in LH pulse frequencies from approximately 1 pulse every 60 min before initiation of T treatment to 1 pulse every 100-150 min at 48 h thereafter. In most cases the deceleration in pulsatile gonadotropin secretion continued, and by 4-8 days of T treatment LH pulse frequencies as low as 1 pulse every 5 h were observed. The onset of the T-induced deceleration in LH pulse frequency was generally associated with an increase in LH pulse amplitude and with a decline in mean LH levels. This LH response in the female to T treatment was similar to that previously reported for male castrates.
mesh_terms: D000818:Animals; D002369:Castration; D005260:Female; D007700:Kinetics; D007986:Luteinizing Hormone / Q000378:metabolism*; D008253:Macaca mulatta; D010507:Periodicity; D013739:Testosterone / Q000494:pharmacology*
chemical_list: D013739:Testosterone; D007986:Luteinizing Hormone