scholarly journals Differential effects of repeated immobilization stress in early vs. late postnatal period on stress-induced corticosterone response in adult rats

2013 ◽  
Vol 534 ◽  
pp. 30-34 ◽  
Author(s):  
Toshihiro Yoshihara ◽  
Yasutaka Yawaka
Keyword(s):  
Immobilization Stress ◽  
Postnatal Period ◽  
Adult Rats ◽  
Differential Effects ◽  
Corticosterone Response

Pituitary-adrenal response to bacterial endotoxin in developing rats

1988 ◽  
Vol 255 (4) ◽  
pp. E525-E530 ◽  
Author(s):  
L. Witek-Janusek
Keyword(s):  
Plasma Corticosterone ◽  
Neonatal Rat ◽  
Bacterial Endotoxin ◽  
Plasma Acth ◽  
Adult Rats ◽  
Age Related ◽  
Corticosterone Response ◽  
Adrenal Response ◽  
Old Rats ◽  
Related Pattern

The neonatal rat is very sensitive to the lethal effects of bacterial endotoxin. Because of the adaptive importance of pituitary-adrenal secretions to stress, this study examined the ontogeny of the plasma corticosterone and adrenocorticotropic hormone (ACTH) responses to endotoxin. The lethal sensitivity of young rats to endotoxin ranged from 0.5 to 30 mg/kg (ip) in the 1- to 21-day-old rat. After endotoxin treatment, the 1- and 2-day-old rat showed marked elevations of corticosterone similar in magnitude to that seen in 21-day-old and adult rats; however, significantly depressed corticosterone increments were observed in the 5-, 10-, and 14-day-old rats. This age-related pattern of adrenocortical secretion was correlated with the developing rat's corticosterone response to exogenous ACTH. In contrast, endotoxin administered to 5-, 10-, and 14-day-old rats resulted in increments of plasma ACTH similar to those observed in the 21-day-old and adult rats. Although plasma ACTH levels increased by 84-127% in the 1- and 2-day-old rats, these increases were significantly less than those of rats at all other ages tested. Thus the newborn rat mounts an effective corticosterone response to endotoxin, loses this ability between ages 5-14 days, and regains this response at 21 days of age. Because the hyporesponsive ages exhibit a marked increase in ACTH secretion, the loss of the adrenocortical response to endotoxin appears to be a result of a depressed responsiveness of the adrenal cortex to ACTH.

Pituitary-adrenal function after transplantation in rats: dependence on age of the adrenal graft

1986 ◽  
Vol 250 (1) ◽  
pp. E87-E93
Author(s):  
W. C. Engeland
Keyword(s):  
Plasma Corticosterone ◽  
Adrenal Function ◽  
Adrenocortical Function ◽  
Elevated Plasma ◽  
Plasma Acth ◽  
Adult Rats ◽  
Adrenal Cells ◽  
Adrenal Tissue ◽  
Corticosterone Response

Comparisons of resting plasma adrenocorticotropin (ACTH) and corticosterone in the morning and afternoon were made among adult rats bearing regenerated adult adrenal grafts, neonatal (day 1) adrenal grafts, adult adrenal capsule grafts, or intact adrenals. In the morning plasma ACTH and corticosterone were similar in all rats. In the afternoon, plasma ACTH was elevated in rats bearing neonatal adrenal grafts or adult adrenal capsule grafts, but not in rats bearing whole adult adrenal grafts. There was no difference in afternoon plasma corticosterone among rats bearing transplanted adrenals, although afternoon plasma corticosterone was decreased in rats bearing transplants compared with rats with intact adrenals. Thus the increased plasma ACTH after adrenal transplantation cannot be explained entirely by decreases in resting plasma corticosterone. Adrenal responsiveness to ACTH was tested at 5 wk after transplantation in the afternoon by measuring the plasma corticosterone response to submaximal doses of ACTH. The responsiveness was decreased in rats bearing transplants. In addition, responsiveness was inversely related to the age of the grafted adrenal tissue. Adrenals regenerated from adult adrenals were more responsive than adrenals regenerated either from neonatal adrenals or from adult adrenal capsules. The findings suggest that following adrenal transplantation reestablishment of normal pituitary-adrenocortical function does not occur in rats bearing adrenals regenerated from immature adrenal cells. In addition, comparable alterations occur after regeneration of adrenal tissue from neonatal adrenal cells and adult adrenal capsular cells. Elevated plasma ACTH associated with adequate plasma corticosterone in rats bearing adrenals regenerated from immature adrenal cells may result from chronic alteration in responsiveness to steroid feedback.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Differential effects in male adult rats of lifelong coconut oil exposure versus during early-life only

2019 ◽  
Vol 55 ◽  
pp. 17-27 ◽  
Author(s):  
Fernanda Torres Quitete ◽  
Egberto Gaspar de Moura ◽  
Geórgia Correa Atella ◽  
Patricia Cristina Lisboa ◽  
Elaine de Oliveira
Keyword(s):  
Early Life ◽  
Coconut Oil ◽  
Adult Rats ◽  
Male Adult ◽  
Differential Effects ◽  
Oil Exposure

Differential effects of FSH and testosterone on the maintenance of spermatogenesis in the adult hypophysectomized rat

1989 ◽  
Vol 121 (1) ◽  
pp. 49-NP ◽  
Author(s):  
J. M. S. Bartlett ◽  
G. F. Weinbauer ◽  
E. Nieschlag
Keyword(s):  
Silicone Elastomer ◽  
Seminiferous Tubules ◽  
Adult Rats ◽  
Intact Control ◽  
Testosterone Treatment ◽  
Differential Effects ◽  
Adult Rat ◽  
Low Levels ◽  
Pachytene Spermatocytes

ABSTRACT In order to clarify further the role of FSH in the maintenance of spermatogenesis, adult rats were treated with purified human FSH (2 × 5 IU/day per rat), testosterone (1·5 cm silicone elastomer implant) or a combination of both hormones for 2 weeks following hypophysectomy. After hypophysectomy alone, no elongate spermatids were observed and the numbers of pachytene spermatocytes and round spermatids observed were reduced when compared with untreated controls. Testosterone supplementation alone qualitatively maintained the formation of elongate spermatids in most seminiferous tubules, whilst in FSH-treated rats increased numbers of round spermatids and pachytene spermatocytes were observed when compared with hypophysectomized animals. Formation of elongate spermatids, however, did not occur under FSH treatment alone. A combination of FSH and testosterone treatment maintained spermatogenesis in an almost quantitative fashion. Numbers of pachytene spermatocytes and round spermatids were maintained at about 80% of levels seen in intact control animals. Treatment with FSH or testosterone alone maintained testis weights at significantly higher levels than those seen in hypophysectomized controls (FSH, 0·79 ± 0·05 g; testosterone, 0·81 ± 0·07 g; hypophysectomized, 0·50 ± 0·04 g). Animals treated with FSH and testosterone showed testis weights 20% below control values (1·22 ± 0·05 vs 1·51 ± 0·06 g; P <0·05). No increases in intratesticular or intratubular androgen concentrations or in testosterone: dihydrotestosterone ratios were observed in any of the hormone-treated groups when compared with hypophysectomized controls. In all hypophysectomized animals testicular androgen concentrations were reduced to <5% of control values. The results obtained in this study suggest that FSH is involved in the maintenance of spermatogenesis in the adult rat and that the effects of FSH are not mediated through changes in intratesticular androgens. Low levels of testosterone in combination with FSH can almost quantitatively maintain spermatogenesis in adult rats. Journal of Endocrinology (1989) 121, 49–58

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