摘要:

This study reports the effects of precociously inducedpuberty upon basal serum corticosterone levels and the response to ether stress (ES) in maturing female rats. Precocious puberty was produced by 25 IU pregnant mare’s serum gonadotrophin (PMS) given at 9 a.m. to 26-day-old rats. On days 28 and 30 PMS-treated rats had higher resting values of corticosterone (B) than did saline-treated rats. On day 35, resting B was greatly depressed in PMS-treated rats in comparison to normal controls. On day 28 the response to ES was less sustained in PMS-treated rats whereas at 35 days of age it was very depressed at all time intervals. Ovariectomy at 21 days of age prevented the post-ovulatory depression of basal and stress-evoked serum B after PMS. It is concluded that the onset of puberty stimulates adrenal function and that after ovulation the PMS-stimulated ovary suppresses adrenal functio

ISSN:0028-3835    

DOI:10.1159/000122240

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

The effects of castration andtestosterone treatment on pineal and retinal hydroxyindole-O-methyl transferases (HIOMT) were investigated in male rats. Pineal and retinal HIOMT activities decreased 24–72 h after cas-tration. Testosterone propionate (TP) (0.1–1 mg/day) stimulated pineal HIOMT which higher doses inhibited significantly; TP (0.1–5 mg/day) increased retinal HIOMT activity. The simultaneous administration of norepinephrine hydrochloride (NE) (250–400 µg) partially reversed the stimulation of pineal HIOMT caused by 0.5 mg/day of TP, and potentiated the inhibition induced by 5 mg/day of TP. NE reversed the TP-induced stimulation of retinal HIOMT. Testosterone was readily taken up and retained by the pineal gland; the radioactivity recovered from the pineal 60 min after a single injection of 3H-testosterone did not differ significantly from that present in the prostate, a classical androgen target organ. In contrast, the retina exhibited the lowest uptake of radioactivity among several organs. The testosterone-induced changes in the pineal HIOMT activity plus the significant amounts of radioactivity found in the pineal after 3H-testosterone administration, suggest that the pineal may be a target organ for a

ISSN:0028-3835    

DOI:10.1159/000122241

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

The effects of neurogenic and systemic stresses onhypothalamic and adenohypophysial cAMP content were studied. Acute neurogenic stress caused a rise in cAMP content in both organs. However, it was not significant when compared to the control animals. In contrast, systemic stress caused a significant decrease in hypothalamic cAMP and a significant rise in adenohypophysial cAMP content. Repeated neurogenic stresses caused a decrease of cAMP content in both organs, however again the difference was not significant when compared to control animals. The present data indicate that the content of cAMP in hypothalamus and adenohypophysis may change according to the type of stress imposed.

ISSN:0028-3835    

DOI:10.1159/000122242

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

An attempt has been made to detect variations inlevels of pineal metabolic activity of rats of three ages: 31 days, 10 weeks, and 1 year. Weight, total protein content, electrophoretic pattern of the soluble proteins, and the free amino acids’ pool of the gland were examined. Absolute weights and total protein content of pineals showed an increase with age but the concentration of protein per mg pineal remained the same at all three ages studied. The electrophoretic pattern of soluble proteins in the pineal is similar at all ages studied, with only quantitative variations occurring between the various bands at different ages. The fast-moving proteins, comprising about 20 % of all soluble proteins, are present in considerably higher proportions in the immature rats; the reverse situation exists with the very slow-moving fraction, representing about 50% of all proteins measured. Certain amino acids were found to increase in their proportions during aging. Others are at their peak in immature rats. The data presented give some basic information on metabolic factors operating at several stages of life and do not appear to reflect a status of lower pineal function in aged animal

ISSN:0028-3835    

DOI:10.1159/000122243

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Brattleboro rats with a genetic defectin antidiuretic hormone (ADH) synthesis are profoundly polydipsic and have a substantially at-tenuated light-dark distribution of drinking when compared to intact rats maintained on an alter-nating cycle of 12 h of light and 12 h of darkness. Twice daily injections of vasopressin tannate markedly reduced water consumption of Brattle-boro rats and also re-established nearly normal nocturnal drinking patterns. The depressive effects of constant light on water intake of albino rats were abolished by nephrectomy; this response may ordinarily depend on ADH-mediated renal water retention. The light-mediated decrease in fluid intake was attenuated by adrenalectomy although nocturnal drinking patterns and phase-shifting of drinking rhythms were normal in these rats. Intact Long-Evans rats were far less responsive than albino rats in that they did not decrease their daily water intake when placed in constant light; responsiveness to continuous illumination was increased in Long-Evans rats by lesions that bilaterally interrupted the superior accessory and primary optic tracts. These components of the central visual projections may inhibit responsiveness to constant light, possibly by modulating activity of the inferior accessory optic tracts.

ISSN:0028-3835    

DOI:10.1159/000122244

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Compared to the results in control animals and in animalsreceiving large volumes of normal saline, infusions of large volumes of hypotonic and hypertonic saline resulted in decreased plasma prolactin in the hypotonic group and in decreased pituitary prolactin and elevated plasma prolactin in the hypertonic group. Changes in plasma prolactin were independent of the large fluid volumes used. The evidence is interpreted as indicating that alterations in serum osmolality may be a significant factor in controlling prolactin secretion.

ISSN:0028-3835    

DOI:10.1159/000122245

出版商:S. Karger AG    

年代:1974

数据来源: Karger