On the correlation of luteinizing hormone-releasing hormone, luteinizing hormone, follicle-stimulating hormone, and prolactin levels in plasma of women with normal menstrual cycles

Abstract

During seven follicular, five periovulatory, and seven luteal days of the menstrual cycle, concentrations of luteinizing hormone-releasing hormone (LHRH), luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin (PRL), total estrogen (TE), and progesterone (P) were measured every 20 minutes over a 3 or a 5 hour period in samples of venous plasma obtained from women with normal menstrual cycles. Episodic peaks of LHRH, LH, and PRL and less pronounced elevations of FSH were observed. Correlation analysis of the study demonstrated the following: (1) During early follicular and late luteal days, a synchrony was observed between LHRH and LH pulses and trends. There was a positive correlation between LHRH and LH levels only during the early follicular days (p < 0.05), demonstrating a probable LHRH control of LH release. (2) When TE and TE/P concentrations increased during the late follicular and early luteal days, respectively, no correlation was present between LHRH and LH levels and trends. (3) Neither a synchrony nor a correlation was detectable between LHRH and FSH pulses or levels during any of the cycle days. (4) A statistical correlation existed between LH and PRL concentrations during various days of the cycle, more specifically during the periovulatory period, suggesting a common release mechanism for these two pituitary hormones.