Influence of castration and testosterone replacement on hypothalamic tyrosine hydroxylase activity in the rat

Summary Hypothalamic tyrosine hydroxylase (TH) activity of castrate rats is modulated by testosterone propionate (TP) in vivo. Kinetic studies revealed that bothV _max andK _m were virtually unaltered for substrate tyrosine in the presence of an excess of DMPH₄ cofactor. TP replacement to castrate rats increased theK _m for added DMPH₄ cofactor, whileV _max decreased. These results suggest that TP decreases TH activity of castrate rats by inhibiting the enzymereduced pteridine cofactor complex.     

Influence of castration and testosterone replacement on hypothalamic tyrosine hydroxylase activity in the rat.

Hypothalamic tyrosine hydroxylase (TH) activity of castrate rats is modulated by testosterone propionate (TP) in vivo. Kinetic studies revealed that both Vmax and Km were virtually unaltered for substrate tyrosine in the presence of an excess of DMPH4 cofactor. TP replacement to castrate rats increased the Km for added DMPH4 cofactor, while Vmax decreased. These results suggest that TP decreases TH activity of castrate rats by inhibiting the enzyme-reduced pteridine cofactor complex.     

Modifications of RNA-containing structures of dorsal bulbocavernosus muscle of rat after castration and testosterone administration

Riassunto Nel muscolo bulbocavernoso dorsale (elevatore dell'ano) di ratto per effetto della castrazione, e rispettivamente della susseguente somministrazione di testosterone, si producono notevoli modificazioni, in senso inverso, in strutture contenenti RNA e che sono importanti per la sintesi proteica (nucleoli e ribosomi citoplasmatici).

---

---

Supported by Muscular Dystrophy Associations of America Inc. and Consiglio Nazionale delle Ricerche, Roma, Italy.     

Increase in serum testosterone in newborn rats]

The changes in serum testosterone and dihydrotestosterone concentrations have been measured in the newborn Rat, before, during and up to 6 hrs after birth. A sudden and transient increase of serum testosterone has been found between 0 and 2 hrs. At 4 hrs, the value returns to that found in the foetus at the end of gestation.     

Effects of castration,estradiol and testosterone on tubulin levels of the medial basal hypothalamus and the adenohypophysis of the rat

Summary Tubulin levels of the medial basal hypothalamus (MBH) were greater in male than in female rats. Orchidectomy brought about a decrease of MBH tubulin concentration, whereas testosterone injection augmented it in the MBH and adenohypophysis. Estradiol administration augmented MBH tubulin and protein concentration.This study was supported in part by grants from the Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina (CONICET) (grant No. 6638), and the Programa Latinoamericano de Investigación en Reproducción Humana (PLAMIRH 2.3.1.75 R).     

Effect of castration and testosterone administration on the noradrenaline content of the vas deferens and the seminal vesicle of the guinea-pig

Zusammenfassung Die Noradrenalinkonzentration im Vas deferens und den Vesiculae seminales erhöht sich nach Kastration, wird aber nach Behandlung mit Testosteron leicht vermindert. Der gesamte Noradrenalingehalt erfährt jedoch nach keiner der beiden Behandlungen eine bedeutende Veränderung verglichen mit unbehandelten Kontrollorganen. Das bedeutet, dass Androgene keinen ausgesprochenen Einfluss auf die adrenergische Innervation per se haben, sondern hauptsächlich Gewebe, wie Glattmuskel- und sekretorische Zellen, influieren.     

The effect of castration, testosterone and estradiol on 14C-serotonin metabolism by organ cultures of male rat pineal glands

The pineal gland of the male rat does not appear to rely on prior conversion of testosterone to estradiol for the stimulant effect of testosterone on pineal melatonin and 5-methoxytryptophol synthesis.     

The effect of castration,testosterone and estradiol on14C-serotonin metabolism by organ cultures of male rat pineal glands

Summary The pineal gland of the male rat does not appear to rely on prior conversion of testosterone to estradiol for the stimulant effect of testosterone on pineal melatonin and 5-methoxytryptophol synthesis.     

Cytochrome oxidase activity in different hypothalamic areas. Influence of castration

Resumen En el presente trabajo se ha estudiado la actividad de la citocromooxidasa en diversas areas hipotalamicas de animales machos castrados y con terapia sustitutiva. Los resultados demonstraron que la castración deprime la actividad de la enzima en el hipotálamo anterior y posterior. La posible implicancia de estos hallazgos con cambios en la cadena respiratoria producidos por la castration es discutida en el trabajo.

---

---

Supported by Consejo Nacional de Investigaciones Científicas y Técnicas.     

Effects of castration, estradiol and testosterone on tubulin levels of the medial basal hypothalamus and the adenohypophysis of the rat.

Tubulin levels of the medial basal hypothalamus (MBH) were greater in male than in female rats. Orchidectomy brought about a decrease of MBH tubulin concentration, whereas testosterone injection augmented it in the MBH and adenohypophysis. Estradiol administration augmented MBH tubulin and protein concentration.