Early Follicular Stage Research Articles

Levels of serum LH in rhesus monkeys after intrapituitary infusion of synthetic LH-RH or median eminence extracts.

Serum levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) of Macaca mulatta females were compared by radioimmunoassay after iv and intrapituitary administration of sheep (o) and rabbit (ra) median eminence extracts (SME) and synthetic LH-releasing hormone (LH-RH). Both intrapituitary infusion and iv injection of oSME and raSME caused nearly equal and significant (p < 0.05) elevations in serum levels of LH within 30 min. Intrapituitary infusion of 40 μg of LH-RH into rhesus at each of 3 stages–days 6 to 7, 11 to 14, or 20 to 23–of their menstrual cycles also caused significant, but equal, increases in serum LH. In contrast, an iv injection of 40 or 85 ng LH-RH during the early follicular or periovulatory stages of the cycle failed to elevate serum LH or FSH significantly above preinjection levels. Since the concentrations of serum LH after LH-RH never approached the LH levels observed during the spontaneous midcycle surge regardless of the LHRH dosage, its mode of administration, or t...