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Light and social exposure: complimentary effect on pituitary gonadal function

MEI-FANGCHENG- Rutgers Newark, N.J. 07102 (U.S.A.)

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The State University, Institute of Animal Behavior,

Testicular hypertrophy response was used as a measurement for relative effect of Iight and social effect on neurosecretory activity in hypothalamo-hypophysial complex. Right testis (larger of the two) were removed from male doves and were weighed. Birds were then assigned to various combination of ( I ) short 11s.normal light cycle, and (2) isolation vs. social stimulation. At the end of 4 weeks all birds were laporatomized. The left testis was removed, weighed and expressed in percentage weight of right testis for each bird. The main results are (1) testicular hypertrophy is complete in 4 weeks in 14 h light cycle. This response is absent for birds kept in 8 h light cycle - testes were even smaller than their pre-castration size. However, this insufficient pituitary response to unilateral castration in short light group can be facilitated by periodic exposure to stimulation female. This effect is not attributable to added light exposure associated with female-exposure period. The results were discussed in terms of existing hypothalamic neurosecretory system. Inhibition effects of “neo-natal” estrogenization on the sexual behavior of the male rat and modifications of the genital tract A. SOULAIRAC AND M. L. SOULAIRAC - Department of Psychophysiology, Faculty of Sciences, University of Paris VI, Paris (France)

Young rats given 10 pg estradiol benzoate between the 2nd and 5th days after birth present a very striking inhibition of sexual behavior at adulthood. The greatest effect is seen when estradiol is administered on postnatal days 4 and 5. The inhibition is not abolished by testosterone administration, but some positive behavioral responses are obtained using neurostimulating drugs (for example, caffeine). In these animals, development of the genital tract is markedly impaired; spermatogenesis is suppressed, mainly following administration on postnatal days 4 and 5, but androgenic interstitial activity is maintained. The possibility of an elective injury of some nervous structures by estrogen at some especially critical periods of central nervous system development is discussed. The role of growth hormone in brain development and behavior V. R. SARA AND L. LAZARUS - Gavvan Institute of Medical Research, St. Vincent’s Hospital, Sydney 2010 (Australia)

The factors regulating in ufero brain growth have yet to be determined. Variation

Light and social exposure: complimentary effect on pituitary gonadal function.

368 FREE COMMUNICATIONS Light and social exposure: complimentary effect on pituitary gonadal function MEI-FANGCHENG- Rutgers Newark, N.J. 07102 (U...
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