Sterility and Delayed Vaginal Opening Following Electrolytic Lesions Placed Neonatally in the Medial Preoptic Area in Female Rats

Abstract

SynopsisElectrolytic lesions were placed in the preoptic area or in the middle and posterior hypothalamus of female rats within 48 hrs after birth. Vaginal opening was delayed significantly in rats having the medial preoptic area (mPOA) destructed as compared to sham-operated animals and those given lesions in the other parts of the hypothalamus.Only rats with the mPOA completely destructed developed the anovulatory syndrome.In these animals, unilateral ovariectomy was not followed by enlargement of its fellow. The present results are not in agreement with those of previous workers that electrolytic destructions of the diencephalon induced precocious puberty.The difference may be ascribable to difference in size and locus of lesions.

Induction of Persistent Estrus by Electrolytic Lesions Placed Neonatally in the Hypothalamus of the Female Rat

“…Destruction of the pom-ha area in neonatal female rats has been reported to cause precocious (Horowitz and van der Werff ten Bosch, 1962;Relkin, 1968) or delayed vaginal opening (Hayashi and Orimo,, 1975). In the present experiments, however, the correlation between neonatal placement of brain lesions and the time of vaginal opening was not evident.…”

The role of oxytocin in male and female reproductive behavior

“…The GnRH-fibers are descending along the mesencephalic aqueduct, where they are probably involved in the induction of lordosis via the surrounding PAG (Buma, 1989;Sakuma and Pfaff, 1980;Samson et al, 1980;Sirinathsinghji, 1985;Veening et al, 2012). The involvement of the MPOA in the hormonal control mechanisms was detected early (Freeman and Banks, 1980;Gray et al, 1978;Hayashi and Orimo, 1975;Leipheimer and Gallo, 1985;Moss and Foreman, 1976;Sirinathsinghji, 1986) and so were the stimulating effects of OT on lordosis, about a decade later Caldwell et al, 1989;Kow and Pfaff, 1988;Schulze and Gorzalka, 1991), (though this stimulation depended on the test situation chosen (Whitney, 1986)).…”