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Biomedical subjects

E H Mougey

Publications and source records attributed to E H Mougey.

At least 55 records · Page 3Linked to original sources

Graded footshock stress elevates pituitary cyclic AMP and plasma beta-endorphin, beta-LPH corticosterone and prolactin.

Male rats were subjected to 15 min of various intensities of footshock current (0.0, 0.2, 0.4, 0.8, 1.6, 2.4, 3.2m A) on a variable interval schedule with an average intershock interval of 30 sec (30 shocks/15 min session). Each shock lasted 5 sec. Animals were sacrificed immediately after being removed from the shock box. Two similar studies were conducted. In the first experiment, rats were sacrificed by microwave irradiation and pituitary cyclic AMP levels were determined. In the second study, rats were decapitated and plasma hormones (prolactin, corticosterone, beta-endorphin, beta-LPH) were measured by radioimmunoassay. Although all biochemical indices of stress measured increased as shock intensity increased, some differences among the substrates measured were observed with respect to threshold intensity, range of proportional response and maximal response.

Animals↗

Comparison of stress response in male and female rats: pituitary cyclic AMP and plasma prolactin, growth hormone and corticosterone.

Three potent stressors (forced running, immobilization, and footshock) were found to increase levels of cyclic AMP in the pituitaries of both female and male rats. The pituitary cyclic AMP response in females was generally similar to that observed in males. The tested stressors elevated both plasma corticosterone and prolactin and decreased plasma growth hormone. Plasma corticosterone rose more rapidly in females than in males following stress. Control growth hormone levels were higher in male rats. There was no clear cause and effect relationship between elevations of pituitary cyclic AMP and changes in plasma levels of prolactin, corticosterone, and growth hormone.

Animals↗

Effects of repeated stress on pituitary cyclic AMP, and plasma prolactin, corticosterone and growth hormone in male rats.

The effects of five putative stressors (saline injection, cold exposure, forced running, immobilization, and footshock) on levels of pituitary cyclic AMP, plasma prolactin, corticosterone and growth hormone were examined. In naive rats exposed to 15 min of these stressors for the first time, running, immobilization and footshock increased levels of pituitary cyclic AMP, plasma corticosterone and prolactin and decreased growth hormone, typical of stress response in the rat. Cold exposure only increased corticosterone and saline injection did not affect any measured parameter. In rats chronically exposed to the same stressor (once a day for 15 min) for 10 days immediately prior to the experiment, an attenuated pituitary cyclic AMP and plasma prolactin response was seen upon application of 15 min of that stressor on the day of the experiment, compared to the responses observed in the naive rats.

Animals↗

Specific hormonal and neurochemical responses to different stressors.

The neuroendocrine and neurochemical responses of rats to 5 min of cold exposure versus 5 min of forced immobilization were determined and compared. We found that plasma hormones and brain neurochemical systems responded differently to the two different stressors. Plasma prolactin levels were elevated over 10-fold in the immolilized group, while rising only 2-fold in the cold stress group. Levels of corticosterone were significantly increased and growth hormone levels were decreased in both stressed groups as compared to controls. Levels of cyclic GMP were markedly elevated in 11 brain regions following cold exposure. Surprisingly, no elevation of cyclic GMP was found after forced immobilization. Cyclic AMP, norepinephrine, and dopamine levels throughout the 17 regions of brain examined showed no significant response to 5 min of either stressor. Lesions of the ventral medial tegmental area did not affect the cyclic GMP or neuroendocrine responses to cold stress. Lesion of the nucleus locus ceruleus did not affect the cyclic GMP response but significantly reduced growth hormone levels in the cold-stressed rats.

Animals↗

A prospective study of corticosteroid and catecholamine levels in relation to viral respiratory illness.

Urinary 17-OHCS, epinephrine and norepinephrine levels were studied for one week before and one week after the onset of acute, severe Adenovirus 4 respiratory illness in 12 Army recruits during Basic Combat Training. During the pre-illness period, a tendency was frequently noted for all three hormone levels to show "spiking" elevations two to four days before illness onset. There was also a tendency for 17-OHCS levels to rise on the day before fever onset. The possible relationship of these pre-illness hormonal changes to stressful experiences and, in turn, to altered host resistance to infectious illness is discussed. Following onset of respiratory illness, 17-OHCS, epinephrine and norepinephrine levels all showed about 60 percent increases over the early pre-illness period baseline value. Elevations of these hormones persisted for about four to five days, roughly in correlation with fever duration, with only slight differences in configuration and timing of curves from one hormone to the next. The problem of evaluating which of several independent variables operating concurrently during infectious illness may be responsible for stimulating the final common neuroendocrine pathways is discussed.

17-Hydroxycorticosteroids↗

A radioimmunoassay for tetrahydrocortisol.

A radioimmunoassay for urinary tetrahydrocortisol (THF) is described. Antibodies were produced in rabbits against a THF-monohemisuccinate:bovine serum albumin conjugate. The radioimmunoassay procedure involves enzymic hydrolysis of the urine, extraction with ethyl acetate, radioimmunoassay, and separation of free from bound steroid with Somogyi reagents. The antibody showed some cross-reaction with tetrahydro substance S (36%) which does not occur in urine in appreciable amounts and with tetrahydrocortisone (10%) which does. An analysis of monkey urine extracts before and after tlc purification revealed that the THF antibody was specific enough to permit assay of urines for THF during stress experiments without a purification step. THF values obtained correlated very highly with 17-hydroxycorticosteroid values on the same urines obtained from monkeys during a chair restraint experience (r = 0.97). Also for comparison purposes these same urines were assayed for free THF, total cortisol, and free cortisol. The free (unconjugated) steroids showed the greatest percentage increase over basal levels.

Animals↗

Small groups in programmed environments. Behavioral and biological interactions.

This paper reviews a research program undertaken within a laboratory environment that was designed and constructed to support behavior analyses of individual and group performance effectiveness viewed conceptually within the context of a small-scale human microsociety. Summarized are previous research emphases and findings in relationship to (1) conditions that sustain group cohesion and productivity and that prevent social fragmentation and performance deterioration, (2) motivational effects resulting from the programmed consequences of individual and group performance requirements, and (3) behavioral and biological effects resulting from a change in group size. A more detailed description is presented of the results of a recent series of experiments that were conducted to assess performance and hormonal effects of replacing an established group participant with a novitiate member. The significance of these investigative undertakings is to be understood in terms of emergent environmental, motivational, and behavioral-biological principles having practical relevance for the establishment and maintenance of small-scale human social systems.

Environment, Controlled↗

Comparison of the effects of CRF and stress on levels of pituitary cyclic AMP and plasma ACTH in vivo.

We have previously reported that acute stress increases levels of rat pituitary cyclic AMP in vivo. The present study was conducted to test the hypothesis that stress-induced increases in pituitary cyclic AMP in vivo were mediated via CRF. We compared the effects of various stressors with the effects of CRF or epinephrine administration on pituitary cyclic AMP and plasma ACTH responses in vivo. Stressors, epinephrine or CRF increased levels of pituitary cyclic AMP. Pituitary cyclic AMP response to either immobilization or CRF was much greater at light onset than at lights off in rats maintained on a 12 hr light:12 hr dark lighting regimen. In rats with pituitary stalk transections, footshock did not increase levels of pituitary cyclic AMP, suggesting that some factor of central origin was required for this stress response. Exogenous CRF administration did increase levels of pituitary cyclic AMP in stalk-transected rats, while epinephrine increased levels in sham-operated but not in stalk-transected rats. Antisera to CRF markedly decreased pituitary cyclic AMP response to exogenous CRF administered 6 min following antisera and partially attenuated pituitary cyclic AMP response to forced running. Taken as a whole these data support a major role for CRF in the pituitary cyclic AMP response to stress.

Adrenocorticotropic Hormone↗

Effects of soman on neuroendocrine and immune function.

We have previously reported that plasma growth hormone (GH) and prolactin levels were markedly decreased in rats two weeks following a single dose (100 micrograms/kg, SC) of soman. We have now conducted additional experiments to attempt to determine whether neuroendocrine responses to physiological or pharmacological challenge are altered in rat survivors of soman exposure, and whether immune function, which can be affected by circulating hormones, is altered in the soman-exposed rats. In the present study, basal prolactin levels were not significantly lower in the soman-treated rats although prolactin increases in response to physiological or pharmacological challenge were attenuated. Also, basal growth hormone levels in soman survivors were similar to control levels in 2 of 3 experiments in the present report. In the third experiment, growth hormone levels were lower in soman-treated animals. Endocrine abnormalities appeared to be related to the severity of soman insult as assessed by changes in body weight following exposure. Both ACTH and prolactin responses to stress were impaired in a severely affected subpopulation of soman survivors. The thymus, an important immune organ, was decreased in weight in severely affected soman survivors, but other tests of immune function did not show differences between control and soman-exposed rats.

Adrenocorticotropic Hormone↗