Recombinant human activin-A stimulates basal FSH and GnRH-stimulated FSH and LH release in the adult male macaque, Macaca fascicularis
Date
1989-11Author
Schwall, Ralph
Steiner, Robert A.
Bremner, William J.
Mason, Anthony J.
Schmelzer, Charles H.
McLachlan, Robert I.
Dahl, Kristine D.
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Show full item recordAbstract
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.