The preoptico-infundibular LH-RH tract of the rat.
Following partial or total deafferentation of the right side of the medial basal hypothalamus (MBH) of female rats, distribution of luteinizing hormone-releasing hormone (LH-RH) axons in and around the isolated area was studied. Accumulation of the hormone along the cut indicated the directions from which LH-RH axons arrived to the isolated hypothalamic area. A comparison of the intact side of the median eminence (ME) to the deafferented side indicated the areas where the transected LH-RH axons would have ended. It was concluded that: (i) LH-RH axons of the MBH of the rat originate from extrahypothalamic areas and approach the ME through the preoptico-infundibular LH-RH tract; (ii) axons from the lateral fascicles of this tract turn toward the ME under oblique angle, consequently, a paramedian sagittal cut causes primary degeneration of the LH-RH terminals only behind the rostral level of the cut, and diminution of these terminals will last even behind the caudal end of the cut; (iii) the tubero-infundibular tract of the rat does not contain LH-RH axons; and (iv) a certain percentage of the  LH-RH axons in the ME originates from the contralateral side of the brain.
D000344:Afferent Pathways / Q000033:anatomy & histology; D000818:Animals; D001369:Axons / Q000648:ultrastructure; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007031:Hypothalamus / Q000033:anatomy & histology*; D008473:Median Eminence / Q000033:anatomy & histology; D011301:Preoptic Area / Q000033:anatomy & histology*; D051381:Rats; D011919:Rats, Inbred Strains; D014371:Tuber Cinereum / Q000033:anatomy & histology*
D007987:Gonadotropin-Releasing Hormone