PROBLEM: This study was undertaken to assess whether growth hormone (G
H) can stimulate follicle growth and ovarian steroidogenesis via putat
ive GH receptors. METHOD: In vitro perfused rabbit ovary. RESULTS: Ovu
lation occurred in neither the control ovaries nor experimental ovarie
s treated with 100 ng/ml of GH, whereas all ovaries exposed to 50 IU o
f human chorionic gonadotropin (hCG) ovulated. The addition of GH to t
he perfusate significantly stimulated the follicle growth in the absen
ce of gonadotropin. The percent change in follicle diameter in OH-trea
ted ovaries did not differ significantly from that in hCo-treated ovar
ies. Exposure to GH significantly stimulated the meiotic maturation in
the follicular oocytes, as compared with the contralateral control ov
aries. Although the concentration of progesterone in the perfusate did
not differ significantly between GH-treated and control ovaries, GH s
timulated estradiol production by the perfused rabbit ovaries. Rabbit
ovary membranes exhibited high affinity binding sites of hGH (Kd = 6.1
x 10(-9)M). CONCLUSION: GH acts on the rabbit ovary to stimulate the
follicle growth, oocyte maturation, and ovarian estradiol production b
y interacting with the specific receptors located in ovarian plasma me
mbranes.