LH FEEDBACK OF STEROID

Abstract

1) Using a new solid Phase radioimmunoassay where latex particles are used as a solid phase and 24 hr incubation time gives a satisfactory sensitivity and accuracy, urinary IH excretion is measured serially in the patients castrated before and after the menopause, and/or given steroidaal contaceptives.2) Urinary IH begins to increase from the day following castration either in postmenopausal or premenopausal women and reaches a maximum excretion of 150-200 IU/I within 10 days which appeared to be earlier as compared with some previous reports, then falls to the level of 50-100 lU/L.3) Oral administration of mestranal or intramuscular injection of hexeterol and estradiol dipropionate apparently suppress IH excretion in the castrated women.4) Twelve healthy women received a variety of steroidal contraceptives LH excretion was suppressed, unchanged in some and stimulated in the other. In all cases using combined or sequential methods the mid-cycle peak of LH was abolished. But in some these cases a particular LH excretion pattern where basal LH excretion is increased with multiple peaks during follicular phase was recognized, besides the abolishment of the mid-cycle IH peak. A possible mechanism is discussed whereby such IH patern resulted inhibition of ovulation by the medication. Since variable changes of IH excretion on cotinuous low doses of progestogen was recognized, the medication seems to have some actions on hypothalamo-pituitary-ovarian axis.