Kinetics of the irreversible degradation in vivo of free L-threonine during lysine deficiency]

In adult fully grown rats deficient in L-Lysine, the speed of the irreversible degradation of free L-threonine equals 1.60 mmol/24 h/g as calculated for 1 mmol/kg administered. This speed is 23 per cent slower than that determined in non lysine deficient animals. This fact explains at least partially, the paradoxical resistance of the adult rat to the lysine deficiency.     

Effect of thymectomy on immune response in adult rats

Zusammenfassung Röntgenbestrahlung thymectomi-sierter Ratten ergab eine abgeschwachte Immunreaktion. Für eine Immunreaktion adulter Tiere scheint jedoch der Thymus nicht notwendig zu sein. In Abhängigkeit von Zeit und Alter der Tiere zeigten sich Unterschiede in der Stärke der Immunreaktion.     

The effect of early weaning on spermiogenesis in adult rats

Zusammenfassung Junge, vorzeitig (18 Tage nach der Geburt entwöhnte Ratten) zeigen im Alter von 12 Monaten Schädigungen im spermiogenen Hodenepithel. 12 Tage später entwöhnte Ratten entwickeln sich normal. Die beobachteten Schädigungen treten im Alter von 6 Monaten noch nicht auf.     

Transplantation of brain tissue in the brain of adult rats

Summary Brain tissues obtained from rat embryos were transplanted in the forebrain and/or cerebellum of the adult rats. The transplants survived, grew and achieved normal cellular and cytoarchitectural differentiation. They had become anatomically integrated with the host brain. The animals did not show any obviously detectable abnormal behavior or pathology of the brain. The transplants survived as long as the animals did suggesting that they had become a part and parcel of the host brain.Supported by research grants NS-08817 and CA-14650 from N.I.H.     

Compensatory hypertrophy of the leydig cells in hemiorchidectomized adult rats

Summary Hemiorchidectomy in adult rats results in hypertrophy of the Leydig cells in the remaining testis. The other parts of the testis appear to be unaffected. Supported by the Swedish Medical Research Council (project 12X-05935) and the Harald Jeansson and Magn Bergvall Foundations.     

Effects of postnatal progesterone treatment on ovarian function in adult rats

Summary Long-lasting postnatal progesterone administration in female rats induced an early or delayed ovulatory failure with persistent vaginal estrus. Short-term treatment was ineffective. The beginning and incidence of ovulatory failure appeared to depend on the beginning and duration of progesterone treatment. The necessary duration of progesterone administration exceeds the critical postnatal steroid sensitive period of sexual differentiation of the hypothalamus. Moreover, long-lasting progesterone treatment results in ovulatory failure even if started after termination of this period.