摘要:

Administration of crude and semipurified beef hypothalamic extracts to normal male rats resulted in a considerable degranulation of acidophil, thyrotropic and gonadotropic cells of the adenohypophysis. This effect was evidenced from 10 to 20 min after intracarotid injection of these extracts. At 60 min, the three groups of cells showed moderate hypertrophy, and the chromophobe cells also showed some degree of enlargement. By 90 min, acidophils were apparently normal, whereas thyrotrophs and gonadotrophs were partially degranulated and vacuolized. These effects coincided with a drop in pituitary FSH (follicle-stimulating hormone) and LH (luteinizing hormone), as evidenced by specific bioassays in animals injected with similar extracts. The control animals, whether sham-operated or injected with saline, vasopressin or brain cortical extracts, did not show any degranulation in the adenohypophyseal cells. This investigation demonstrated that the well-known effect of hypothalamic extracts on pituitary tropins can also be evidenced at a histological level.

ISSN:0028-3835    

DOI:10.1159/000121909

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

A single injection of 62.5 µg reserpine inhibits ovulation induced in intact immature rats by administration of pregnant mare’s serum (PMS) and human chorionic gonadotrophin (HCG) when reserpine is given ½ to 6½ h before HCG. Increases or decreases in the amount of HCG are not reflected by similar changes in the ovulatory response of reserpinized rats, indicating that reserpine’s action is not due to an antagonism of HCG. The monoamine oxidase inhibitor (MAOI), pargyline, partially reverses the inhibitory effect of reserpine, although it has no effect on ovulation per se. Previous experiments with reserpine suggested that its inhibitory effect on ovulation was due to its ability to block luteinizing hormone (LH) release. The present experiments circumvent the necessity for consideration of LH release, since HCG is given exogenously in amounts adequate to induce ovulation. It is clearly evident from our results that reserpine exerts a direct effect on the ovary in addition to its effect at the hypothalamo-hypophyseal

ISSN:0028-3835    

DOI:10.1159/000121910

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

The reduced amount of neurosecretory material (NSM) that is stored in pituitary glands of hereditary hypothalamic diabetes insipidus (DI) rats compared with glands of normal rats reflects their oxytocin content, since DI rats are apparently unable to synthesize vasopressin. If oxytocin were synthesized exclusively in the paraventricular nucleus (PVN), then complete destruction of this nucleus in DI rats should result in the disappearance of all NSM from the pars nervosa. Complete bilateral ablation of the PVN in DI rats was achieved with lesioning electrodes in only 2 out of 24 animals, with varying degrees of destruction of the PVN in the remainder. The rats were sacrificed one month after lesioning and the amount of NSM remaining in the pars nervosa was assessed histologically. In general, the results show a rough, direct correlation between the number of PVN cells remaining in the hypothalamus and the amount of stored NSM in the pituitary. Nevertheless, the 2 rats with complete PVN ablation still had pituitary NSM. These results suggest that although the PVN may be primarily concerned with oxytocin synthesis, it does not seem to be the exclusive site of oxytocin production. Considerable amounts of this hormone are apparently synthesized elsewhere, the supraoptic nucleus being the most likely source.

ISSN:0028-3835    

DOI:10.1159/000121911

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

The CD (Charles River) strain of rats differs in several important respects from our inbred Osborne Mendel (O-M) strain. The critical period for the ovulatory surge of gonadotropin in proestrus is less sharply limited in CD rats. They are much more refractory to preoptic (POA) electrochemical stimulation for ovulation, not only in normally cycling females, but strikingly so in androgen-sterilized (TP) females, as well as in rats having spontaneous persistent estrus (PE). In proestrous 4-day cyclic CD females ‘blocked’ with pentobarbital, a much larger stimulus (100 µA × 30 sec = 3000 µcoulombs) was required to fully ovulate all subjects than was needed in similar O-M rats (10 µA × 20 sec = 200 µcoulombs). While 5/6 O-M PE rats ovulated in response to massive unilateral POA stimulation (3000 µcoulombs), all of 6 CD PE rats failed to ovulate. Even bilateral POA stimulation with these parameters induced ovulation in only 3/10 rats. O-M TP rats had low POA thresholds close to those of cyclic O-M females, while only 1/6 CD TP rats gave even a partial response (5 tubal ova) to massive bilateral stimulation. CD TP rats also differed from O-M TP rats by secreting abundant prolactin in spite of the constant estrus. This was shown by prominent milk cysts in the mammary glands at 8–9 months of age and by spontaneous pseudopregnancy after corpora lutea were induced by LH injection. O-M TP rats had no mammary development and experienced only a short diestrus after LH injection. Whether there is a common basis for these strain differences remai

ISSN:0028-3835    

DOI:10.1159/000121912

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

The olfactory bulbs were removed in 2- to 3-month-old virgin Wistar rats; one month later, the animals were tested for precocious and oestrous mating activity during 5-day cycles. The mating frequencies observed in control and operated animals, respectively, were 35/87 and 4/50 during the night following day 3 (dioestrus 3), 36/42 and 31/38 during the night following day 4 (prooestrus), and 42/70 and 17/30 during the night following day 3, following injection of a single dose of 10 µg oestradiol. Precocious ovulation was triggered by coitus in unoperated as well as in operated oestradiol-primed animals. In operated animals, no disturbance of spontaneous ovulation frequencies was recorded, but a small decrease in the mean number of corpora lutea was observed

ISSN:0028-3835    

DOI:10.1159/000121913

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

The hypophysial stalk and the median eminence were cauterized electrically in rats 20–24 h after birth, and the growth and histogenesis and functional capacities of the endocrine glands of these rats were examined 20–23, 40–43, and 60–70 days after the operation. The arcuate nuclei showed degenerative alterations in rats with lesions of the median eminence. The supraoptic and paraventricular nuclei showed degenerative changes in rats with an isolated pituitary stalk. In all these animals, the growth and development of the gonads were greatly reduced, and the functional activities of the thyroid and adrenal glands were also affected. The results indicated that normal growth and development of endocrine organs may require intact vascular and afferent neuronal coordinations between the hypothalamus and the hypophysis for the transportation of factors releasing hypophysial trophic h

ISSN:0028-3835    

DOI:10.1159/000121914

出版商:S. Karger AG    

年代:1970

数据来源: Karger

ISSN:0028-3835    

DOI:10.1159/000121915

出版商:S. Karger AG    

年代:1970

数据来源: Karger