Effects of chemotherapy-induced testicular damage on inhibin, gonadotropin, and testosterone secretion: a prospective longitudinal study.
To investigate the role of inhibin in the control of follicle-stimulating hormone (FSH) secretion, we have measured levels of immunoreactive inhibin (ir-inhibin), inhibin B, Pro-alpha C containing inhibins, FSH, luteinizing hormone (LH), and testosterone in twelve men with hematological malignancies before, during, and after chemotherapy. Inhibin B levels fell significantly by 1 month from a mean +/- SE baseline level of 273.2 +/- 32.8 pg/mL, reaching a nadir of 52.6 +/- 15.3 pg/mL at 4 months (P < 0.0001). FSH levels increased within the first month from a baseline level of 3.9 +/- 0.6 IU/L, reaching a peak level of 22.4 +/- 3.3 IU/L at 4 months (P < 0.0001). FSH and inhibin B were significantly and inversely correlated (r = 0.69, P < 0.0001). Pro-alpha C containing inhibin levels increased significantly (P < 0.05) at 3 months and were significantly and positively correlated with FSH (r = 0.38, P = 0.002). LH levels increased significantly but to a much lesser extent than FSH, the increase becoming evident only 4 months after treatment commenced (P < 0.03). Levels of ir-inhibin and testosterone remained unchanged throughout the study. These data provide strong support to the hypothesis that inhibin B is the physiologically important form of inhibin in men, negatively regulating FSH secretion at the pituitary. Furthermore, they suggest that FSH stimulates inhibin alpha-subunit secretion by the testis.
Wallace
E M
EM
Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia. Euan.Wallace@med.monash.edu.au
Groome
N P
NP
Riley
S C
SC
Parker
A C
AC
Wu
F C
FC
D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects* / Q000627:therapeutic use; D005640:Follicle Stimulating Hormone / Q000097:blood; D006062:Gonadotropins / Q000378:metabolism*; D019337:Hematologic Neoplasms / Q000097:blood / Q000188:drug therapy; D006801:Humans; D007265:Inhibins / Q000097:blood / Q000737:chemistry / Q000378:metabolism*; D008137:Longitudinal Studies; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood; D013737:Testis / Q000187:drug effects* / Q000378:metabolism*; D013739:Testosterone / Q000097:blood / Q000378:metabolism*
D006062:Gonadotropins; D011498:Protein Precursors; D013739:Testosterone; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone