Recombinant human activin-A stimulates basal FSH and GnRH-stimulated FSH and LH release in the adult male macaque, Macaca fascicularis.
Activin-A is a homodimer of the beta A inhibin subunit that stimulates FSH secretion by pituitary cells in vitro; however, the physiological relevance of this effect is unknown. We have examined whether recombinant human activin-A (activin-A; 80 micrograms/kg/day iv infusion for 50.5 h) has in vivo bioactivity in the adult male macaque (n = 5). Serum FSH and LH bioactivity and serum testosterone (T) levels were measured on 2 control days and after 24 and 48 h of activin-A administration. Basal FSH levels increased significantly (p less than 0.05) by 17% at 24 h and 82% at 48 h during activin-A administration. No changes in basal LH or T levels were seen. The FSH and LH responses to GnRH (5 micrograms/kg, iv bolus) increased significantly (p less than 0.05) by 117% and 55% after 48 h of activin-A, respectively. A small (16%), but statistically significant (p less than 0.05), increase in the T response to the GnRH challenge was also noted. These data are preliminary evidence in support of a physiological role for activin-A in the control of gonadotropin secretion in the male primate.
McLachlan
R I
RI
Department of Medicine University of Washington, Seattle 98195.
Dahl
K D
KD
Bremner
W J
WJ
Schwall
R
R
Schmelzer
C H
CH
Mason
A J
AJ
Steiner
R A
RA
D028341:Activins; D000818:Animals; D001681:Biological Assay; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D006107:Granulosa Cells / Q000187:drug effects; D006801:Humans; D007265:Inhibins / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D008252:Macaca fascicularis; D008297:Male; D051379:Mice; D011994:Recombinant Proteins / Q000494:pharmacology*; D012016:Reference Values
D011994:Recombinant Proteins; D028341:Activins; D007987:Gonadotropin-Releasing Hormone; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone