Plasma substance-P and substance-K and gonadal steroids in relation to the gonadotropin surge in normal human reproductive cycles.

PURPOSE: This study was designed to examine changes in peripheral plasma substance-P and -K levels, their association with follicle-stimulating hormone and luteinizing hormone release in normal reproductive cycles in humans, and their correlation with plasma estradiol and progesterone.

METHODS

Fourteen healthy, normally menstruating women underwent daily blood sampling (cycle day 4, 4-14 days) for measurement of estradiol, progesterone, luteinizing hormone, and follicle-stimulating hormone, substances-P and -K, and daily transvaginal ultrasounds assessing follicular growth and documentation of ovulation.

RESULTS

Estradiol peaked on day 13, luteinizing hormone and follicle-stimulating hormone peaked on day 14, and progesterone began an exponential increase on about day 13.

CONCLUSIONS

In contrast to other experimental designs using in vitro or in vivo rat or monkey tissue, peripheral levels of substances-P (P = 0.8391) and -K (P = 0.3205) reflected no modulation related to midcycle gonadotropin release in cycling woman.