Serum levels of luteinizing hormone, follicle-stimulating hormone and progesterone throughout the menstrual cycle of rhesus monkeys

Abstract

Serum levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and progesterone were determined in serum samples obtained throughout the menstrual cycle of rhesus females by radioimmunoassay. During the follicular phase of the cycle, LH levels averaged 300 ng/ml, increased to peak levels of 1400 ng/ml at midcycle, reached a nadir at 200 ng/ml during the mid-luteal phase, then rose to follicular phase levels with the onset of menstruation. FSH levels were 350 ng/ml during the early follicular phase of the cycle, fell somewhat to 200 ng/ml just before the midcycle preovulatory surge, then rose to peak levels of 1500 ng/ml to coincide with the rise in LH. FSH levels also reached their nadir of 150 ng/ml during the midluteal phase of the cycle and then rose with the onset of menstruation. Progesterone levels were low during the follicular phase of the cycle and increased to peak levels of 6 ng/ml during the luteal phase of the cycle. © 1973 by The Endocrine Society.