EFFECTS OF ADRENAL-MEDULLA TRANSPLANTATION INTO THE 3RD VENTRICLE ON THE ONSET OF PUBERTY IN FEMALE RHESUS-MONKEYS

To test the hypothesis that prepubertal exposure of LHRH neurons to a source of catecholamines and neuropeptides accelerates the onset of pu berty, me examined the effects of autologous adrenal transplantation i nto the base of the third ventricle of the brain in juvenile female rh esus monkeys at 11-13 months of age. The adrenal medulla, which contai ns catecholamines and neuropeptide Y (NPY), was cut into small pieces and mixed with gelfoam in artificial CSF and injected into the third v entricle, adjacent to LHRH neurons and their neuroterminals. Sham cont rol monkeys received artificial CSF with gelfoam alone. Animals were m onitored for signs of pubertal development. While menarche was not alt ered by adrenal transplantation, the timing of first and second ovulat ions occurred significantly (P < 0.05) earlier in adrenal-transplanted monkeys. Histological examination indicated that the grafts survived in all transplanted monkeys. The presence of catecholamines and NPY in graft tissue was confirmed by tyrosine-hydroxylase-positive, dopamine beta-hydroxylase-positive, and NPY-positive cells. Endogenous LHRH fi bers were observed innervating the graft tissue. We conclude that: (1) adrenal medulla transplantation into the third ventricle accelerates the age of first ovulation; (2) this is likely due to neuroactive subs tances (e.g., catecholamines and NPY) from the graft tissue; and (3) g rafted adrenal medulla tissue can survive for at least 30-40 months. H owever, the age of menarche was not accelerated by this grafting, sugg esting that an additional mechanism (e.g., removal of tonic inhibition ) may be necessary for the onset of puberty. (C) 1996 Academic Press, Inc.