EFFECT OF SEX AND AGE AT GONADECTOMY ON THE SEBACEOUS RESPONSE TO PROGESTERONE

1977 ◽  
Vol 73 (1) ◽  
pp. 67-70 ◽  
Author(s):  
SAM SHUSTER ◽  
WENDY M. HINKS ◽  
A. J. THODY
Keyword(s):  
Adult Female ◽  
Adult Male ◽  
Female Rats ◽  
Male Rats ◽  
Adult Males ◽  
Adult Rat ◽  
Sebum Production ◽  
Males And Females ◽  
Sebum Secretion

SUMMARY The effect of progesterone on the rate of sebum secretion was examined in intact and gonadectomized rats. In intact, adult, male rats, progesterone administered for 3 weeks decreased sebum secretion; after castration of adult males, progesterone increased sebum secretion and an even greater response occurred in males castrated at 21 days of age. In intact, adult, female rats progesterone slightly increased sebum production. As in the male, the response was affected by the time of gonadectomy, a greater response occurring after spaying at 21 days compared with 10 weeks of age. Thus, the response to progesterone in the adult rat differs in intact males and females and is affected by changes in the endocrine environment induced by gonadectomy, especially near the time of puberty.

scholarly journals Leptin inhibits testosterone secretion from adult rat testis in vitro

1999 ◽  
Vol 161 (2) ◽  
pp. 211-218 ◽  
Author(s):  
M Tena-Sempere ◽  
L Pinilla ◽  
LC Gonzalez ◽  
C Dieguez ◽  
FF Casanueva ◽  
...  
Keyword(s):  
Adult Male ◽  
Reproductive Function ◽  
Serum Testosterone ◽  
Testicular Tissue ◽  
Male Rats ◽  
Adult Males ◽  
Adult Rats ◽  
Adult Rat ◽  
Testosterone Secretion

Leptin, the product of the ob gene, has emerged recently as a pivotal signal in the regulation of fertility. Although the actions of leptin in the control of reproductive function are thought to be exerted mainly at the hypothalamic level, the potential direct effects of leptin at the pituitary and gonadal level have been poorly characterised. In the present study, we first assessed the ability of leptin to regulate testicular testosterone secretion in vitro. Secondly, we aimed to evaluate whether leptin can modulate basal gonadotrophin and prolactin (PRL) release by incubated hemi-pituitaries from fasted male rats. To attain the first goal, testicular slices from prepubertal and adult rats were incubated with increasing concentrations (10(-9)-10(-7) M) of recombinant leptin. Assuming that in vitro testicular responsiveness to leptin may be dependent on the background leptin levels, testicular tissue from both food-deprived and normally-fed animals was used. Furthermore, leptin modulation of stimulated testosterone secretion was evaluated by incubation of testicular samples with different doses of leptin in the presence of 10 IU human chorionic gonadotrophin (hCG). In addition, analysis of leptin actions on pituitary function was carried out using hemi-pituitaries from fasted adult male rats incubated in the presence of increasing concentrations (10(-9)-10(-7) M) of recombinant leptin. Serum testosterone levels, and basal and hCG-stimulated testosterone secretion by incubated testicular tissue were significantly decreased by fasting in prepubertal and adult male rats. However, a significant reduction in circulating LH levels was only evident in adult fasted rats. Doses of 10(-9)-10(-7) M leptin had no effect on basal or hCG-stimulated testosterone secretion by testes from prepubertal rats, regardless of the nutritional state of the donor animal. In contrast, leptin significantly decreased basal and hCG-induced testosterone secretion by testes from fasted and fed adult rats. In addition, 10(-9) M leptin inhibited LH and FSH secretion by incubated hemi-pituitaries from fasted adult males, whereas, at all doses tested, it was ineffective in modulating PRL release. Our results show that leptin, depending on the state of sexual maturation, is able to inhibit testosterone secretion acting at the testicular level. Furthermore, the present data suggest that the actions of leptin on the reproductive system are complex and are probably carried out at different levels of the hypothalamic-pituitary-gonadal axis.

scholarly journals Endocrine regulation of sex differences in hepatic histidase activity

1985 ◽  
Vol 231 (3) ◽  
pp. 785-787 ◽  
Author(s):  
C A Lamartiniere
Keyword(s):  
Sex Differences ◽  
Adult Female ◽  
Adult Male ◽  
Pituitary Hormones ◽  
Female Rats ◽  
Male Rats ◽  
Endocrine Regulation ◽  
Pituitary Glands

Hepatic histidase activity in adult female rats is twice that in adult male rats. Hypophysectomy and thyroidectomy result in a significant increase in hepatic histidase activities in males, but not in females. This effect on histidase is reversed by the exogenous administration of tri-iodothyronine, but not by ectopic pituitary glands or purified pituitary hormones.

scholarly journals Effects of Age and Sex on the Healing of Acetic-Acid Induced Ulcerative Colitis in Adult Wistar Rats

2021 ◽  
pp. 63-73
Author(s):  
Serah F. Ige ◽  
Waliyat O. Aremu ◽  
Bolade S. Olateju ◽  
Victor A. Oladipupo ◽  
Adedayo T. Adekola
Keyword(s):  
Ulcerative Colitis ◽  
Superoxide Dismutase ◽  
Acetic Acid ◽  
Adult Female ◽  
Adult Male ◽  
Wistar Rats ◽  
Female Rats ◽  
Male Rats ◽  
Cell Numbers ◽  
Age And Sex

Aims: Ulcerative colitis is a disease of the bowel that occurs in all ages and affects both males and females. This research study was designed to investigate the effect of age and sex on the healing of colitis in rats. Methodology: Twenty - eight rats were randomly distributed into four groups of seven animals per group; adult male rats, mid age male rats, adult female rats and mid age female rats. Mid age and adult Wistar rats were 7- 8weeks and 14 weeks old respectively. Colitis was induced through a single intra-colonic instillation of 7% acetic acid (1mL/100g body weight) and allowed to heal for 14 days. Blood samples were obtained for analysis. Colon samples were also obtained for histomorphological study and biochemical assays (Myeloperoxidase activities, Superoxide dismutase, Glutathione, Catalase and Malondialdehyde) levels. Results: There was no significant difference in Malondialdehyde concentration, catalase, Superoxide dismutase, Myeloperoxidase, Platelet Distribution Width, Platelet Count, Basophil cell numbers, Eosinophil cell numbers, platelet cells, Mean Platelet Volume , Mean Cell Volume and white blood cells across the groups. The Glutathione concentration in mid age male rats was significantly increased when compared with adult male rats. The haemoglobin , Lymphocytes and Mean Cell Haemoglobin levels were increased while neutrophils and monocyte levels were decreased in the younger female rats. The histomorphological study revealed poorly preserved surface epithelia layer of the colon in adult male rats while mid age male and female rats showed moderately preserved surface epithelia layer, adult female rats showed normal surface epithelia layer. Conclusion: Mid age rats heal faster than adult rats while in terms of sex, female rats tends to heal faster than male rats.

THE ACTION OF AN ANTI-ANDROGENIC STEROID, 17α-METHYL-B-NORTESTOSTERONE, ON SEBUM SECRETION IN RATS TREATED WITH TESTOSTERONE

1967 ◽  
Vol 38 (2) ◽  
pp. 181-185 ◽  
Author(s):  
F. J. EBLING
Keyword(s):  
Female Rats ◽  
Sebaceous Glands ◽  
Androgenic Steroid ◽  
Sebum Production ◽  
Sebum Secretion ◽  
Do So

SUMMARY An anti-androgenic steroid, 17α-methyl-B-nortestosterone was shown to reduce sebum production in spayed female rats treated simultaneously with testosterone. The sebum production was assessed by measuring the increase in the amount of ether-extractable hair fat over a period of 8 days immediately after washing the rats. Testosterone increased the secretion of sebum mainly by stimulating mitosis in the sebaceous glands and it was shown that the anti-androgenic steroid acted at this site, i.e. by suppressing mitosis. These effects were in contrast to the action of oestradiol which also depressed sebaceous activity, but appeared to do so by interfering with synthesis in the sebaceous cells.

Insulin sensitivity, leptin, adiponectin, resistin, and testosterone in adult male and female rats after maternal-neonatal separation and environmental stress

2018 ◽  
Vol 314 (1) ◽  
pp. R12-R21 ◽  
Author(s):  
Hershel Raff ◽  
Brian Hoeynck ◽  
Mack Jablonski ◽  
Cole Leonovicz ◽  
Jonathan M. Phillips ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adult Male ◽  
Rat Model ◽  
Female Rats ◽  
Male Rats ◽  
Male And Female ◽  
Neonatal Hypoxia ◽  
Male And Female Rats ◽  
Plasma Leptin ◽  
Neonatal Separation

Care of premature infants often requires parental and caregiver separation, particularly during hypoxic and hypothermic episodes. We have established a neonatal rat model of human prematurity involving maternal-neonatal separation and hypoxia with spontaneous hypothermia prevented by external heat. Adults previously exposed to these neonatal stressors show a sex difference in the insulin and glucose response to arginine stimulation suggesting a state of insulin resistance. The current study used this cohort of adult rats to evaluate insulin resistance [homeostatic model assessment of insulin resistance (HOMA-IR)], plasma adipokines (reflecting insulin resistance states), and testosterone. The major findings were that daily maternal-neonatal separation led to an increase in body weight and HOMA-IR in adult male and female rats and increased plasma leptin in adult male rats only; neither prior neonatal hypoxia (without or with body temperature control) nor neonatal hypothermia altered subsequent adult HOMA-IR or plasma adiponectin. Adult male-female differences in plasma leptin were lost with prior exposure to neonatal hypoxia or hypothermia; male-female differences in resistin were lost in the adults that were exposed to hypoxia and spontaneous hypothermia as neonates. Exposure of neonates to daily hypoxia without spontaneous hypothermia led to a decrease in plasma testosterone in adult male rats. We conclude that neonatal stressors result in subsequent adult sex-dependent increases in insulin resistance and adipokines and that our rat model of prematurity with hypoxia without hypothermia alters adult testosterone dynamics.

scholarly journals Risk-based Decision Making in Rats: Modulation by Sex and Amphetamine

2020 ◽  
Author(s):  
Dannia Islas-Preciado ◽  
Steven R. Wainwright ◽  
Julia Sniegocki ◽  
Stephane E. Lieblich ◽  
Shunya Yagi ◽  
...  
Keyword(s):  
Decision Making ◽  
Sex Differences ◽  
Gonadal Hormones ◽  
Risky Choice ◽  
Female Rats ◽  
Male Rats ◽  
Risky Decision Making ◽  
Risky Decision ◽  
17Β Estradiol ◽  
Males And Females

AbstractDecision-making is a complex process essential to daily adaptation in many species. Risk is an inherent aspect of decision-making and it is influenced by gonadal hormones. Testosterone and 17β-estradiol may modulate decision making and impact the mesocorticolimbic dopamine pathway. Here, we explored sex differences, the effect of gonadal hormones and the dopamine agonist amphetamine on risk-based decision making. Intact or gonadectomised (GDX) male and female rats underwent to a probabilistic discounting task. High and low doses of testosterone propionate (1.0 or 0.2 mg) and 17β-estradiol benzoate (0.3 μg) were administered to assess acute effects on risk-based decision making. After 3-days of washout period, intact and GDX rats received high or low (0.5 or 0.125 mg/kg) doses of amphetamine and re-tested in the probabilistic discounting task. Under baseline conditions, males made more risky choices during probability discounting compared to female rats, particularly in the lower probability blocks, but GDX did not influence risky choice. The high, but not the low dose, of testosterone modestly reduced risky decision making in GDX male rats. Conversely, 17β-estradiol had no significant effect on risky choice regardless of GDX status in either sex. Lastly, a higher dose of amphetamine increased risky decision making in both intact males and females, but had no effect in GDX rats. These findings demonstrated sex differences in risk-based decision making, with males showing a stronger bias towards larger, uncertain rewards. GDX status influenced the effects of amphetamine, suggesting different dopaminergic regulation in risk-based choices among males and females.

Effects of adults on survival and recruitment of Peromyscus leucopus

1987 ◽  
Vol 65 (10) ◽  
pp. 2519-2523
Author(s):  
Gregory H. Adler ◽  
Mark L. Wilson ◽  
Michael J. DeRosa
Keyword(s):  
Adult Female ◽  
Adult Male ◽  
Peromyscus Leucopus ◽  
Survival Rates ◽  
Adult Males ◽  
Control Grid ◽  
Young Males ◽  
Young Females ◽  
Breeding Seasons ◽  
And Control

A population of Peromyscus leucopus (white-footed mouse) in northeastern Massachusetts was manipulated for 3 years to determine the effects of adults on survival and recruitment. Two experimental grids were established, from which either all adult males or all adult females were removed continually. The effects of these two manipulations were compared with demography on a control grid. Manipulations had no apparent effect on breeding intensity of young, survival rates of adults, or residency rates of adults and young. Recruitment of adult males was higher on the adult male removal grid than on the control grid. Recruitment rates of adult males and of young males and young females were lower on the adult female removal grid than on the control grid. Survival rates of young males were higher on the adult female removal grid than on the control grid; this effect may have been due to either reduced adult female residency or adult male recruitment. All differences between experimental and control grids were noted only during breeding seasons. Adult males apparently limited recruitment of adult consexuals. The effects of manipulations on other measured parameters were inconclusive because of high immigration rates of adult males onto the adult male removal grid and reduced recruitment of adult males and decreased production of young on the adult female removal grid.

Cimetidine-induced prolactin release in rats The effect of sex and gonadal steroids

1987 ◽  
Vol 114 (2) ◽  
pp. 178-184 ◽  
Author(s):  
Hajime Watanobe ◽  
Kazuo Takebe
Keyword(s):  
Anterior Pituitary ◽  
Male Rats ◽  
Minor Role ◽  
Adult Males ◽  
Adult Age ◽  
Significant Difference ◽  
Males And Females ◽  
Plasma Prl ◽  
A Minor

Abstract. The cimetidine-induced plasma Prl response was examined in rats of both sexes. First, 10 week old intact adult males and females (dioestrous) were compared. There was no significant difference in the Prl response to cimetidine between the two groups, despite the fact that in adult females the anterior pituitary Prl content was 4 times greater than in males. Second, the effect of gonadal state in adult age on the Prl response to cimetidine was examined in both sexes. In male rats, gonadectomy at the age of 6 weeks significantly reduced the plasma Prl response as well as the pituitary Prl content, both of which were sufficiently restored by testosterone replacement. However, in females, neither gonadectomy at the age of 6 weeks nor subsequent oestradiol replacement affected the Prl response to cimetidine, despite the fact that gonadectomy significantly reduced and oestradiol treatment significantly enhanced the pituitary Prl content. Third, possible permanent effects of the postnatal gonadal milieu on the cimetidine-induced Prl response and the pituitary Prl content were examined in both sexes by castration at varying postnatal ages. The ratio of plasma Prl response to pituitary Prl content was similar in all castrated males. In females, however, the ratio decreased with increasing castration age. In conclusion, the mechanism of cimetidine-induced Prl release is less sex-dependent than are the mechanisms of Prl release by other Prl secretagogues. First, this may be due to a minor role of oestrogen in females in determining the Prl response to cimetidine. Second, the postnatal ovarian secretions may exert a permanent inhibition of the development of the cimetidine-mobilized anterior pituitary Prl pool.

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