Acta Physiologica 50. (1977)

1. szám - PHYSIOLOGIA - Hahn Z.-Lénárd L.: Sex-dependent consequences of bilateral pallidal lesion after postpuberal castration in rats

Acta Physiologien Academiae Scientiarum Hungáriáié, Tomus 50 (1), pp. 19—26 (1977) SEX-DEPENDENT CONSEQUENCES OF BILATERAL PALLIDAL LESION AFTER POSTPUBERAL CASTRATION IN RATS By Z. Hahn* and L. Lénárd DEPARTMENT OF GYNAECOLOGY AND OBSTETRICS, UNIVERSITY MEDICAL SCHOOL, PÉCS, AND NEUROPHYSIOLOGY RESEARCH GROUP OF THE HUNGARIAN ACADEMY OF SCIENCES AT THE INSTITUTE OF PHYSIOLOGY, UNIVERSITY MEDICAL SCHOOL, PÉCS (Received May 12, 1976) Consequences (aphagia, adipsia, body weight loss, postoperative mortality) of bilateral pallidal lesion are sex-dependent, all of them being more severe in males than in females. Castration prior to lesion failed to eliminate the sex-dependence. Artificial food and water administration was ineffective in abolishing the difference in body weight changes between males and females. Body weight of females did not exceed their preoperative weight even 90 days after lesion. A close positive correlation was found in females between weight on the 90th postoperative day and the lowest body weight in the first 14 days after lesion. Vaginal cycles of non-castrated females were normal between the 75th and 87th postoperative days. Sex-dependent activity of a metabolic factor independent of postpuberal sexual steroid levels may be responsible for the effect. Several data (Morgane 1961; Gold 1967; Morgane 1969; Morgane and Jacobs 1969; Levine et al. 1971; Levine and Schwartzbaum 1973; Kent and Grossman 1973) suggest that a pallidohypothalamic system is involved in the regulation of food and water intake. Electrolytic lesions at various sites presumably belonging to this system result in aphagia and/or adipsia as well as in weight loss and consequent death of the animals. Forced food and water administration fails to compensate the body weight loss after lesion of the pallidohypothalamic tract suggesting thus the involvement of metabolic factors. The pallidohypothalamic tract and the lateral part of the lateral hypothalamus were shown to represent a system involved in the neural control of intermediate metabolism (Morgane 1961, 1969). Previous experiments indicate that the consequences (especially death rate) of bilateral lesions placed into the globi pallidi are sex-dependent (LÉNÁRD et al. 1975). Sex-dependence of body weight loss may, however, be ascribed to that of food and water intake as well as to differences in water and fat content of the two sexes. Previous data (Lénárd et al. 1975) suggest, however, that there is no correlation between postoperative food and water consumption and recovery or the chance for long survival in either of the two sexes. The only clearly decisive factor found was the sex of the animals. Data on the effect of sexual steroids on body weight regulation (Hervey and Hervey * Present address: Institute of Physiology, University Medical School, Pécs. 2' Acta Physiologica Academiae Scientiarum Hungaricae 50, 1977

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