Effect of testosterone on the hypothalamic-pituitary-gonadal axis of pinealectomized and pineal-intact male rats.

Previous studies indicate that steroid hormones alter pineal biochemistry, and it has been suggested that at least part of the negative feedback effect of steroid hormones on pituitary gonadotropin release may be mediated by the pineal gland. In this study, pinealectomy did not alter the inhibitory effect of testosterone on neuroendocine-gonadal activity in the male rat, suggesting that the pineal gland does not mediate the response of the rat hypothalamic-pituitary axis to testosterone.     

Pineal indols and testosterone affect exploratory activity of male rats

Summary The testosterone level has an inverse relation to activity in the open-field test. This is more important in red light than in white light. Pineal indols do not disturb this action. Some of these results are consistent with the assumption that androgens play a role on the exploratory activity of adult subjects.     

Pineal indols and testosterone affect exploratory activity of male rats

The testosterone level has an inverse relation to activity in the open-field test. This is more important in red light than in white light. Pineal indols do not disturb this action. Some of these results are consistent with the assumption that androgens play a role on the exploratory activity of adult subjects.     

Gonadotropin receptors,cAMP and testosterone in estrogenized male rats

Summary In neonatally estrogenized and PMSG-treated rats, binding of¹²⁵I-HCG to testicular receptors correlates with levels of plasma testosterone, but not with formation of cAMP.     

Role of pituitary in the thyroid hypertrophy of pinealectomized rats

Zusammenfassung Epiphysektomie bei verschiedenen Gruppen weiblicher Ratten ergab Zunahme des Schilddrüsengewichtes. Diese war postoperativ in der ersten Woche besonders stark und perennierte während 7 Wochen der Experimentdauer. Entsprechende Gewichtszunahme der Schilddrüse resultiert auch nach Epiphysektomie bei hypophysenlosen Tieren.

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This work was assisted in part by a research grant from the Consejo Nacional de Investigaciones Cientificas y Técnicas, Republica Argentina.     

The effect of neonatal administration of testosterone and oestradiol on the liver nuclear volume of male and female rats

Zusammenfassung Wirkung von Testosteron oder Östradiol auf die Grösse bzw. das Kernvolumen der Leberzellen von neugeborenen männlichen und weiblichen Ratten. Testosteron verursachte vor allem bei weiblichen Tieren eine erhebliche Volumenzunahme der Leberzellenkerne, während Kastration eine Verminderung der Polyploidie zur Folge hatte.

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The work was done during the tenure of the Widnes Cancer Research Fellowship. The author wishes to thank Dr.J. C. Davis for the helpful discussion and the North West Cancer Research Fund for the financial support.     

Spontaneous adenomata of the hypophyseal anterior lobe in aged pinealectomized rats

Zusammenfassung Es wurden Vorkommen und Eigenschaften des Hypophysenadenoma bei altersschwachen Ratten nach Pinealektomie beschrieben. Trotzdem in Tumoren zirbeldrüsenloser Tiere grössere Parenchymbildung und grösserer Blutgehalt erscheinen, können die vorliegenden Ergebnisse keinen entscheidenden Unterschied bestätigen.

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This investigation was supported in part by PHS research grant No. GM-05219 from the National Institute of General Medical Sciences, NIH, Public Health Service, USA, and the Miller Institute for Basic Research in Science, University of California, Berkeley (California).     

Effect of testosterone on the levels of nucleic acids and proteins in the uropygial gland of the male quail

A close correlation was evidenced between the length of a silastic capsule filled with testosterone propionate and the resulting plasma concentrations in testosterone in castrated male Quail. 5 days after the beginning of the treatment, testosterone induced in the spleen glands a conspicuous increase in total RNA, DNA and protein contents.     

Effect of glucocorticoids injected into pregnant female mice and rats on weight of male sexual glands in adult offspring and testosterone level in fetus in genotype-dependent

Injection of corticosterone into CBA/Lac, C57BL/6J and BALB/c mice, or hydrocortisone into aggressive and domesticated rats, on days 16 and 18 of pregnancy decreased the weight of sexual glands in adult male offspring of the C57BL/6J and domesticated mothers but increased these values in male offspring of the CBA/Lac and aggressive mothers. When injected into pregnant aggressive and domesticated rats, corticosterone affected testosterone levels in 21-day-old male fetuses. The changes were also genotype-dependent and followed the course of changes in the weight of the accessory sex glands in adults. It is suggested that glucocorticoids given during the prenatal period can effect plasma testosterone levels of male fetuses and the development of the sexual glands in a genotype-dependent manner.     

Long term replacement therapies with testosterone propionate and human chorionic gonadotrophin in hypophysectomized adult male rats

Zusammenfassung Langzeitversuche mit hypophysektomierten Ratten ergaben, dass Testosteron oder HCG allein die Spermiogenese, Hodengewicht, nicht aufrechterhalten konnten.

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Klinische Forschung der Schering AG.     

Effect of sex hormones on plasma cholesterol in castrated and noncastrated male rats

The administration of estradiol to both castrated and noncastrated male rats was associated with significantly increased plasma cholesterol levels as compared to controls, the estradiol in the noncastrated rats overriding the tendency of testosterone to lower plasma cholesterol.     

Effect of sex hormones on plasma cholesterol in castrated and noncastrated male rats

Summary The administration of estradiol to both castrated and noncastrated male rats was associated with significantly increased plasma cholesterol levels as compared to controls, the estradiol in the noncastrated rats overriding the tendency of testosterone to lower plasma cholesterol.Acknowledgement. This work was supported by USPHS Grant NHLBI 17721.     

The effect of daily evening isoproterenol administration on reproductive organ growth in male rats treated neonatally with testosterone propionate

Summary Daily evening injections of isoproterenol extended the period of high pineal N-acetyltransferase activity and retarded the growth of testes, seminal vesicles and prostate in rats treated neonatally with testosterone propionate.The authors are grateful to Mrs Marie Svobodová for her skillful technical assistance.     

Effect of estrogens on LH- and FSH-levels in prepuberal male and female androgenized rats

Summary This paper has demonstrated that neonatal androgenization increases in prepuberal male and female rats the FSH-levels without changes in LH, indicating that the sexual differences in the control of FSH is a relevant process that takes place during the differentiation of the hypothalamus.Supported by a grant from the Consejo Nacional de Investigaciones Cientificas y Técnicas, Rep. Argentina.Acknowledgment. We are grateful to NIAMD, Rat Pituitary Program, for the reagents for the radioimmunoassays.     

Post-weaning differential housing and testosterone secretion in male mice

Summary The effect of different densities of animals per cage on basal testosterone secretion and its response to some stimuli was studied in prepuberal male mice. Mice housed with 110 or 55 cm² of floor space per animal showed the same basal serum testosterone and hCG-induced testosterone release. Likewise, in a second experiment, the same basal serum testosterone and a similar response to acute noise stress were found in mice housed at 132, 66 or 22 cm² of floor space per animal. These results suggest that post-weaning crowding did not affect Leydig cell function in male mice.     

Effects of repeated administration of potassium canrenoate (SC-14266) on serum gonadotrophin,prolactin, testosterone and progesterone in male rats

Summary Chronic administration of potassium canrenoate (SC-14266), a water-soluble anti-aldosterone agent, increased serum LH levels in male rats without altering serum levels of FSH, prolactin, testosterone and progesterone. The increase in serum LH may be due to the anti-androgenic effect of potassium canrenoate.Acknowledgments. The authors thank the Rat Pituitary Hormone Distribution Program, NIAMDD, NIH and Dr A.F. Parlow for radioimmunoassay materials.