Norepinephrinergic involvement in the neuronal mechanism regulating compensatory ovarian hypertrophy

The data presented support the existence of a neural connection between the gonads and the hypothalamus. The morphological substrate of this neural pathway is unknown. Concerning the functional significance of this neural connection it seems possible that it plays a role in the development of compensatory ovarian hypertrophy and supports the view that a non-hormonal, neural component is involved in the development of compensatory ovarian hypertrophy. The abovementioned data are in good accordance with the observations made on the adrenal gland. Since compensatory organ growth occurs after specific tissue loss in the adrenal cortex, ovary, testis, thyroid gland, kidney, liver and salivary gland one can speculate that the postulated neural connection and its role in the development of compensatory hypertrophy might be a more general phenomenon. On the other hand the fact that after unilateral orchidectomy in rabbit there is a decreased intraocular pressure in the eye opposite to the removed testis (20) and in patients with unilateral testicular lesion pathological changes such as keratoconjunctivitis sicca, reduced tear production, occur in the eye contralateral to the testis affected, it seems possible that afferent nerves arising from the gonads terminate not only in neuroendocrine structures. Further studies are required to prove morphologically the supposed neural pathway between the adrenal, the gonads and the hypothalamus, to investigate its other probable role in the endocrine function and to study whether similar neural mechanism is involved in the development of compensatory hypertrophy of the thyroid, kidney, liver and salivary gland.