A pharmacokinetic and endocrine comparison of recombinant follicle-stimulating hormone and human menopausal gonadotrophin in polycystic ovary syndrome

Abstract

Elevated LH concentrations are frequently encountered in patients with polycystic ovary syndrome (PCOS) and increased LH (either endogenous or superimposed through the use of HMG) may have detrimental effects on reproductive function. In spite of this, FSH-only products and HMG have been used indiscriminately for ovulation induction – on the basis that the administration of HMG to patients with PCOS, who are not receiving GnRH agonists, does not result in significant increases in serum LH concentrations as judged by daily single blood samples. However, both endogenous and exogenous LH have a relatively short terminal half-life and studies have reported normal serum LH, but abnormal urinary LH and emphasized that early morning urinary measurements are more informative than those in serum because they reflect nocturnal LH secretion. Therefore, the present study was undertaken to perform a pharmacokinetic and endocrine comparison of recombinant human FSH and HMG in PCOS patients including LH measurements in the urine. Five PCOS patients receiving s.c. recombinant human FSH (rhFSH) and five PCOS patients receiving i.m. HMG for ovulation induction according to a chronic low-dose step-up regimen underwent blood and urine sampling at the following study points: Point 0 was the day of HCG injection; Points 1 to 5 corresponded to days HCG −1 to −2; −3 to −4; −5 to −6; −7 to −8; and −9 to −10; respectively. Serum hormone measurements included oestradiol, FSH, LH, progesterone, inhibin A, androstenedione, testosterone, and free testosterone index. FSH and LH were also measured daily in 8-h urine samples reflecting overnight renal urine secretion. Hormone concentrations calculated as the area under the curve showed that both FSH and LH concentrations in urine were significantly higher in HMG group than in group rhFSH. It is concluded that both LH and FSH concentrations significantly accumulate in the urine of PCOS patients receiving HMG for ovulation induction in a chronic low-dose protocol as compared with rhFSH treatment.