Effects of the benomyl metabolite, carbendazim, on the hypothalamic-pituitary reproductive axis in the male rat.
Carbendazim (MBC), the bioactive metabolite of the fungicide benomyl, has been reported to induce a number of testicular alterations in male rats. Since it is possible that extragonadal changes contribute to the appearance of such effects, the present study focused on the presence of concurrent endocrine changes in the hypothalamic and pituitary components of the brain-pituitary-testicular axis. Subchronic administration of MBC (50, 100, 200 or 400 mg/kg) was found to cause a dose-related elevation in serum follicle stimulating hormone (FSH) and pituitary luteinizing hormone (LH). Values for prolactin and thyroid-stimulating hormone remained unchanged. No statistical differences in gonadotropin-releasing hormone concentrations were present in mediobasal hypothalamus, although an elevation in anterior hypothalamic values was found at the low dose, followed by a dose-related decline. These findings demonstrate that previously reported gonadal differences following subchronic exposure to carbendazim are accompanied by alterations elsewhere in the reproductive system which appear to involve both changes in Sertoli cell-pituitary feedback signals and direct effects of the compound on the central nervous system.
Goldman
J M
JM
NSI Technology Services, Environmental Sciences, Research Triangle Park, NC 27709.
Rehnberg
G L
GL
Cooper
R L
RL
Gray
L E
LE
Hein
J F
JF
McElroy
W K
WK
D000818:Animals; D001562:Benzimidazoles / Q000633:toxicity*; D002219:Carbamates; D005640:Follicle Stimulating Hormone / Q000097:blood / Q000378:metabolism; D005659:Fungicides, Industrial / Q000633:toxicity*; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism; D008297:Male; D009929:Organ Size / Q000187:drug effects; D011388:Prolactin / Q000097:blood / Q000378:metabolism; D051381:Rats; D012016:Reference Values; D013737:Testis / Q000187:drug effects / Q000473:pathology*; D013972:Thyrotropin / Q000097:blood / Q000378:metabolism
D001562:Benzimidazoles; D002219:Carbamates; D005659:Fungicides, Industrial; D007987:Gonadotropin-Releasing Hormone; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D013972:Thyrotropin; C006698:carbendazim