摘要:

A diurnal rhythm in pineal protein was found to occur in mature rats. In the male, a peak level is reached about 4 p.m., preceded by a gradual increase during the period of light and followed by a decrease that arrives at its nadir around midnight. The rhythm is shifted by a 4 h delay in peak and trough in mature female rats. Marked daily fluctuations were also recorded in pineal ribonucleic acid (RNA) of the mature male animals, a peak occurring around noon and a sharp nadir at midnight. No significant changes were noted in RNA levels of female rats, whether immature or adult, although a similar pattern in diurnal rhythm is apparent. While no diurnal changes in pineal deoxyribonucleic acid (DNA) were observed in either males or females, a trend towards higher values at midday and lower ones at midnight was characteristic here, too. The results obtained provide metabolic evidence for reported diurnal nuclear changes and indicate that cellular function is indeed related to nuclear size. The relationship between the diurnal rhythms of the RNA and protein of the pineal and its endocrinologically active indoles is discussed.

ISSN:0028-3835    

DOI:10.1159/000121975

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

Performance of a prelearned conditioned avoidance response (CAR) showed gross deterioration in albino female rats during pregnancy and pseudopregnancy (PSP). To create a PSP-like condition, progesterone and oestradiol were given exogenously, singly and in combination, to different groups of rats. Progesterone alone caused a partial deterioration of behaviour; but when administered in combination with oestradiol, it produced effects on the CAR performance and body weight comparable to those observed in PSP. There was also a good correlation between the behavioural deficits and weight gains resulting from such treatment. Endogenous augmentation of the luteal hormones by prolactin administration in another group produced effects that were comparable to those seen in PSP, although quantitatively poorer. Progesterone, in conjunction with oestrogen, appeared to be responsible for the behavioural deteriorations in the female rats, but was ineffective in the males.

ISSN:0028-3835    

DOI:10.1159/000121976

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

The effects of the decapeptide ACTH-(1–10) and [D-phe7]-ACTH-(1–10) were tested on the rate of extinction of a pole-jumping avoidance response in rats. ACTH-(1–10) in doses of 20, 50, and 100 µg inhibited extinction of the avoidance response 4 h following subcutaneous administration. [D-phe7]-ACTH-(1–10) in doses of 20, 50, and 100 µg facilitated extinction 4 h after injection. Intracerebral implantation of approximately 10 µg of these ACTH-analogues in the freely moving rat had similar effects on extinction of avoidance response when implanted into the region of the rostral mesencephalon and the caudal diencephalon, at the posterior thalamic level, or in the cerebrospinal fluid. Ineffective sites were the nucleus ventralis thalami, the nucleus anterior medialis thalami, the nucleus reuniens, the globus pallidus, the nucleus accumbens, the fornix, and the hippocampus. The results support the hypothesis that the site of action of ACTH and of ACTH-analogues on extinction of an avoidance response is localized in the central nerv

ISSN:0028-3835    

DOI:10.1159/000121977

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

The oxidative activity was determined in the hypothalamus, amygdala, and hippocampus of intact and ovariectomized rats. Following castration, the hypothalamic metabolism was depressed to levels below the diestrus values of the intact rats. The amygdala andhippocampus, on the other hand, presented a sustained high value of oxygen uptake. This is in contrast with the pattern normally seen in the various phases of the estrous cycle, where the QO2 of the amygdala is at its highest value during estrus, while hippocampal QO2 reaches its maximum during diestrus.

ISSN:0028-3835    

DOI:10.1159/000121978

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

The hypothalamic-hypophysial control of basal adrenal cortical function was investigated in three avian species, by means of adenohypophysectomy (HE) and pituitary autografting (AG). HE led to a marked decrease of the plasma corticosterone content: (36 to 43 % of controls in ducks, 54% in pigeons, 46% in quail), and of adrenal corticosterone (16 % in ducks and pigeons, 30 % in quail), while the adrenal aldosterone content remained unaltered. The biological half-life (T½) of 3H-corticosterone showed a twofold increase, and the metabolic clearance rate (MCR) of the hormone was reduced to 60 % of the control values, in the duck. These results are discussed in the light of a possible extra-hypophysial adrenocorticotropic control. Provided the post-operative time lapse was sufficient to offer the grafted ectopic pituitary the possibility of functional resumption, the plasma corticosterone level was maintained at 80 % of the control values in ducks, 77 % in pigeons, and 90 % in quail; the T½and MCR of 3H-corticosterone were also found to be restored. However, the adrenal corticosterone content was low (30 % of the control values in ducks and pigeons, 75% in quail); the adrenal aldosterone level was normal. The relative importance of CRF is discusse

ISSN:0028-3835    

DOI:10.1159/000121979

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

Vasopressor and oxytocic activities were detectable in the pars nervosa of mice with hereditary diabetes insipidus (DI Os/+ strain). This finding shows that the diabetes insipidus of DI mice is due to a primary defect of the kidney and not to vasopressin deficiency. Both activities of the DI mice were significantly higher than in normal mice (VII +/+) when the activities were expressed in terms of the individual. However, when the activity was expressed per mg of dry weight of the pars nervosa, the difference in oxytocic activity of the two groups seemed to be no longer significant, although vasopressor activity was still greater in the DI mice.

ISSN:0028-3835    

DOI:10.1159/000121980

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

The turnover rate of 14C-NE was studied regionally in males of 4 strains of inbred mice. It was found that the highest uptake and most rapid disappearance of this amine was exhibited, in declining order, by the hippocampus, hypothalamus, frontal cortex, and amygdala. Of the 4 strains studied, DBA/2J and SJL/J shared equally the highest turnover rates, while C3H/HeJ consistently exhibited the slowest turnover rates in all the brain regions examined. Because there were no accompanying analyses for bound and free NE, the conclusions regarding the significance of some of the differences found in this study are somewhat limited.

ISSN:0028-3835    

DOI:10.1159/000121981

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

The hypothalamo-neurohypophysial (HN) complex of Funambulus pennanti was studied for the first time using an in situ staining technique. In the bulk-stained preparation, the distribution pattern of the neurons of the supraoptic (SON) and paraventricular nuclei (PVN) and their axonal tracts can be better understood than in tissue sections or in their reconstruction. Neurons of the SON are distributed in three groups: rostral, dorsomedian, and caudal. The PVN is U-shaped, one arm of the U being in close contact with the median component of the SON through the scattered neurons. The axons of the PVN could be traced to the region of the SON and median eminence; but once they merge with the tract of the SON, their identity is lost. In the median eminence, a pair of well-defined median and lateral tracts that are in close contact with the vascular net work are present. Quantitative changes observed in the stainable neurosecretory material in response to osmotic stress are basically comparable to those seen in rats.

ISSN:0028-3835    

DOI:10.1159/000121987

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

The plasma corticosterone response to 3 min of stimulation was investigated in adult male BLU: (LE) rats housed 1 or 4 per cage for 3-4 weeks. In Experiment 1, rats injected with malaria-infected or normal erythrocytes responded in the same way to stimulation applied on day 6 post-infection. Rats housed in groups (G) and alone (A) had the same corticosterone levels 0 or 15 min post-stimulation; but the levels of A-rats remained elevated at 30 min, while those of G-rats had dropped. Experiment 2 determined that this differential pattern occurs at both the peak and trough in the 24 h corticosterone rhythm. Experiment 3 examined the response at 0, 10, 15, 20, 25, or 30 min post-stimulation. Although G- and A-rats had equal values at 10 min, values were lower for G-rats at the other test points, suggesting that G-rats may reach their maximum level earlier than A-rats. The results of the three experiments, taken together, indicated that the most reliable effect of differential housing on plasma corticosterone was on the response pattern over time, rather that the absolute level at any given point in time. In Experiment 4, changing housing conditions after stimulation disclosed that the previously observed differences between G- and A-rats resulted from post-stimulation housing conditions. Caging G- or A-rats with new cage-mates after stimulation increased the magnitude and modified the temporal pattern of the corticosterone response to stimulation, previously grouped rats showing a lower level of response than rats previously housed alone.

ISSN:0028-3835    

DOI:10.1159/000121982

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

The activity of the melatonin-forming enzyme, hydroxyindole-O-methyltransferase (HIOMT), is high in the pineals of rats kept in constant darkness and low in the glands of animals kept in constant light. The sympathetic innervation of the pineal is necessary to maintain this response to light. Following removal of the superior cervical ganglion (ganglionectomy) or section of the preganglionic fibers to the ganglion (decentralization), the pineal HIOMT response to light is lost. In addition, HIOMT levels after decentralization are significantly less than after ganglionectomy and these, in turn, are significantly less than constant-light, control levels. The decreases in pineal HIOMT content produced by ganglionectomy and decentralization are evident within 1 week and become maximal by 2 to 3 weeks after operation. Thereafter, they remain stable for at least 120 days. These data indicate that an intact sympathetic innervation to the pineal is necessary, not only for an HIOMT response to light, but, also, to maintain normal enzyme activity in the gland. The observation of a substantial decrease in HIOMT activity in the squirrel monkey pineal following decentralization suggests that this may be a more general phenomenon in mammals. Despite the effect on pineal HIOMT, denervation of the pineal does not alter the normal estrous cycle of the female rat kept in diurnal light, nor does it affect the alterations in estrous activity produced by prolonged exposure to constant light or blinding. These findings are in accord with the view that light-mediated alterations in pineal function are not essential in the rat to either the maintenance of normal estrous cycles or to estrous responses to conditions of continuous illumination.

ISSN:0028-3835    

DOI:10.1159/000121983

出版商:S. Karger AG    

年代:1971

数据来源: Karger