scholarly journals Hypoxic and hypercapnic ventilatory responses in aging male vs. aging female rats

2009 ◽  
Vol 106 (5) ◽  
pp. 1522-1528 ◽  
Author(s):  
J. M. Wenninger ◽  
E. B. Olson ◽  
C. J. Cotter ◽  
C. F. Thomas ◽  
M. Behan

It is clear that sex hormones impact ventilation. While the effects of the menstrual cycle, pregnancy, testosterone, and progesterone on resting ventilation have been well documented, effects of sex hormones on the hypoxic (HVR) and hypercapnic ventilatory responses (HCVR) are inconclusive. In addition, in no study have systemic sex steroid hormone levels been measured. Age and sex differences in long-term facilitation in response to episodic hypoxia were found in anesthetized rats. The purpose of the present study was to assess the effects of sex and age [young, 3–4 mo; middle age, 12–13 mo; and old, >20 mo] on the HVR and the HCVR of awake rats relative to systemic hormone levels. Based on findings from long-term facilitation studies, we hypothesized that the HVR would be influenced by both sex and age. We found no age-related changes in the HVR or HCVR. However, female rats have a greater HVR than male rats at old age, and at middle age female rats have a greater HCVR than male rats. Additionally, we found no correlation between the minute ventilation/oxygen consumption and the progesterone-to-estrogen ratio during hypoxia or hypercapnia. However, changes in ventilatory responses with age were not similar between the sexes. Thus it is critical to take sex, age, estrous cycle stage, and systemic hormone levels into consideration when conducting and reporting studies on respiratory control.

1993 ◽  
Vol 129 (6) ◽  
pp. 543-547 ◽  
Author(s):  
Shaw-Lang Yang ◽  
Chin Hsu ◽  
Hseng-Kuang Hsu ◽  
Keh-Min Liu ◽  
Ming-Tsung Peng

Neuron density, volume of the area and total neuron number were measured in the medial preoptic area, anterior hypothalamic area and arcuate nucleus of the hypothalamus of young (6-month-old), middle age (14-month-old) and old (22-month-old) male and female rats. Intact male rats did not show neuron loss even in old age, while intact female rats manifested neuron loss in the medial preoptic area, anterior hypothalamic area and arcuate nucleus in old age. Long-term administration of estradiol benzoate to castrated male rats induced neuron loss in the anterior hypothalamic area and arcuate nucleus of the middle age group and in all three areas of the old age group. However, long-term ovariectomy could not prevent neuron loss in these hypothalamic areas in old age. The results suggested that estradiol can have a cumulative impact on the degree of neuron damage and simulate female-type age-related neuron loss in male rats and that there may be the possibility of an intrinsic aging process inducing neuron loss in female rats.


Author(s):  
Shung-Tai Ho ◽  
Tso-Chou Lin ◽  
Chun-Chang Yeh ◽  
Kuang-I Cheng ◽  
Wei-Zen Sun ◽  
...  

Background: Long-term use of opioids for chronic noncancer pain is associated with sex hormone disturbances. The interferences with sex hormones, sexual function, and depression were investigated in patients with chronic noncancer pain. Methods: A cross-sectional multicenter survey was conducted on 170 officially registered outpatients receiving long-term opioid treatment in nine medical centers in Taiwan between October 2018 and July 2019. Serum sex hormone levels were examined after the collection of self-administered questionnaires containing the Taiwanese version of the Brief Pain Inventory, depressive status, and sexual function interference. Results: Among 117 (68.8%) questionnaire responses from 170 enrolled outpatients, 38 women and 62 men completed the sex hormone tests, among whom only 23 (23%) had previously received blood hormone tests. Low serum total testosterone levels were detected in 34 (89.5%) women (<30 ng/dL) and 31 (50%) men (<300 ng/dL). Over 60% of women and men reported reduced sexual desire and function despite a nearly 50% reduction in pain intensity and daily function interference over the previous week after opioid treatment. Women generally had higher risks of a depression diagnosis (p = 0.034) and severe depressive symptoms (p = 0.003) and nonsignificantly lower opioid treatment duration (median 81 vs. 120 months) and morphine milligram equivalent (median 134 vs. 165 mg/day) compared with men. Conclusions: This survey demonstrated the high prevalence of depression diagnosis, low sex hormone levels, and reduced sexual function among Taiwanese patients with chronic noncancer pain receiving prolonged opioid therapy. Regular hypogonadal screenings are recommended for further management.


1990 ◽  
Vol 126 (3) ◽  
pp. 461-466 ◽  
Author(s):  
M. N. Sillence ◽  
R. G. Rodway

ABSTRACT The effects of trenbolone acetate (TBA) on growth and on plasma concentrations of corticosterone were examined in male and female rats. At 5 weeks of age, rats were injected with TBA (0·8 mg/kg) dissolved in peanut oil, or with oil alone, daily for 10 days. In female rats, TBA caused an increase in weight gain (20–38%), a reduction in adrenal weight (19%) and a reduction in plasma concentrations of corticosterone (55%). In contrast, TBA-treated male rats showed no significant increase in weight gain, no significant change in adrenal weight and no reduction in plasma concentrations of corticosterone. The mechanism by which adrenal activity was suppressed in TBA-treated female rats was examined and the response compared with that to testosterone. Female rats (8 weeks old) were injected daily either with oil vehicle, TBA (0·8 mg/kg) or testosterone propionate (0·8 mg/kg). Testosterone increased weight gain (24%), but the growth response to TBA treatment was significantly greater (97%). A reduction in plasma concentrations of corticosterone (45%) was again observed in response to TBA. However, testosterone increased plasma concentrations of corticosterone (52%) above those of control values. Neither androgen affected plasma concentrations of ACTH. Finally, the effects of TBA were examined in 6-week-old female rats, to characterize further the apparent age-related increase in responsiveness. The growth response of 6-week-old rats (60–74%) was intermediate between that seen in 5- and 8-week-old animals. It is concluded that part of the anabolic activity of TBA may be related to a reduction in circulating concentrations of corticosterone. The effect of TBA on corticosterone concentrations differs from that of the natural androgen, testosterone, and does not appear to be mediated by a reduction in plasma concentrations of ACTH. Journal of Endocrinology (1990) 126, 461–466


2003 ◽  
Vol 95 (6) ◽  
pp. 2614-2623 ◽  
Author(s):  
A. G. Zabka ◽  
G. S. Mitchell ◽  
E. B. Olson ◽  
M. Behan

Age and the estrus cycle affect time-dependent respiratory responses to episodic hypoxia in female rats. Respiratory long-term facilitation (LTF) is enhanced in middle-aged vs. young female rats ( 72 ). We tested the hypothesis that phrenic and hypoglossal (XII) LTF are diminished in acyclic geriatric rats when fluctuating sex hormone levels no longer establish conditions that enhance LTF. Chronic intermittent hypoxia (CIH) enhances LTF ( 41 ); thus we further predicted that CIH would restore LTF in geriatric female rats. LTF was measured in young (3-4 mo) and geriatric (20-22 mo) female Sasco Sprague-Dawley rats and in a group of geriatric rats exposed to 1 wk of nocturnal CIH (11 vs. 21% O2 at 5-min intervals, 12 h/night). In anesthetized, paralyzed, vagotomized, and ventilated rats, time-dependent hypoxic phrenic and XII responses were assessed. The short-term hypoxic response was measured during the first of three 5-min episodes of isocapnic hypoxia (arterial Po2 35-45 Torr). LTF was assessed 15, 30, and 60 min postepisodic hypoxia. Phrenic and XII short-term hypoxic response was not different among groups, regardless of CIH treatment ( P > 0.05). LTF in geriatric female rats was smaller than previously reported for middle-aged rats but comparable to that in young female rats. CIH augmented phrenic and XII LTF to levels similar to those of middle-aged female rats without CIH ( P < 0.05). The magnitude of phrenic and XII LTF in all groups was inversely related to the ratio of progesterone to estradiol serum levels ( P < 0.05). Thus CIH and sex hormones influence the magnitude of LTF in geriatric female rats.


Author(s):  
Rene Franco-Elizondo ◽  
Sukanya Pranathiageswaran ◽  
M. Safwan Badr ◽  
Susmita Chowdhuri

2020 ◽  
Vol 36 (6) ◽  
pp. 399-416
Author(s):  
Nurhayat Barlas ◽  
Emre Göktekin ◽  
Gözde Karabulut

The present study was designed to evaluate the effects of di- n-hexyl phthalate (DHP) and di-cyclohexyl phthalate (DCHP) on endocrine organs in rats. Oil control, 20-, 100-, and 500 mg/kg dose groups were selected and administered to pregnant rats on gestational days 6–19 by oral gavage. The neonatal stages of rats continued until postnatal day 20 and the- juvenile stages of rats continued until postnatal day of 32. The rats were allowed to mature until the neonatal and juvenile stages and there after, they were divided into four groups corresponding to the treatment levels. Body and organ weights were recorded, serum was collected, and thyroid, pancreas, pituitary gland, and adrenal gland were removed. There was a decrease in body weights in the 20- and 500mg/kg DHP and in the 20-mg/kg DCHP dose groups in neonatal male rats. In contrast, for female rats, there was an increase in body weights in the 100-mg/kg DCHP dose group and there was a decrease in body weights in the 500-mg/kg DHP dose group. Body weights were increased at 20 and 500 mg/kg in the DHP-exposed juvenile male rats. Serum thyroid-stimulating hormone (TSH) levels were increased in neonatal male rats, while they were increased in the 100-mg/kg DHP group of neonatal and juvenile female rats. Serum triiodothyronine (T3) levels were increased at the high dose of DHP for neonatal male rats and at the low and high dose levels of DCHP for female rats. Serum thyroxine (T4) levels were increased in neonatal rats for DHP. Also, some histopathological changes were observed in the thyroid, pancreas, adrenal, and pituitary gland. In conclusion, it was shown that DHP and DCHP caused negative effects on T3, T4, and TSH hormone levels.


1986 ◽  
Vol 61 (2) ◽  
pp. 780-784 ◽  
Author(s):  
E. H. Schlenker ◽  
M. Goldman

In this study ventilation was evaluated in 12-mo-old male and female rats who had received large doses of aspartic acid neonatally. Rats of both sexes treated with aspartic acid were obese, stunted, and exhibited hypogonadism. Although metabolic rates of the aspartic acid-treated rats were not different compared with sex-matched controls, ventilatory patterns were different. Aspartic acid-treated females breathed with a smaller tidal volume (VT), higher frequency (f), and similar minute ventilation (VE) compared with control females. This pattern is commonly observed in many patients who are obese. The aspartic acid-treated females responded to hypercapnic and hypoxic challenges by increasing f more than VT. Tissue pocket gases (PCO2 and PO2) of aspartic acid-treated females were normal. In contrast, aspartic acid-treated males hypoventilated compared with control males. Tissue pocket gas values suggested that aspartic acid-treated males were hypoxemic and hypercapnic. Moreover, the response of aspartic acid-treated males to hypercapnia was parallel to but was less than that of control male rats. The ventilatory response of aspartic acid-treated male rats to hypoxia was blunted. This study has shown that neonatal administration of aspartic acid causes a decreased ventilation and blunted response to hypoxia in adult male but not female rats.


Sign in / Sign up

Export Citation Format

Share Document