| Abstract: | Concentrations of circulating LH were determined in conscious, free-moving ovariectomized rats. All of the animals had been ovariectomized at 24 days of age. Between 30 and 90 days there was an increase in mean blood LH concentrations; a more vigorous pulsatile release of LH characterized by an increase in amplitude and frequency of LH release; and an elevated responsiveness to LHRH administration. Rats which had been ovariectomized for 1 year still had elevated blood LH levels but had episodic pulses of reduced amplitude and a decrease in responsiveness to LHRH. These data suggest that important alterations occur with age in the neuroendocrine mechanisms responsible for the release of LH. |
