Impaired Prolactin Response to Synthetic Thyrotropin-Releasing Hormone After a 36 Hour Fast

Ai, Vinik; Wj, Kalk; McLaren, H. C.; Paul, Mary

doi:10.1055/s-0028-1093812

Cited by 21 publications

(9 citation statements)

References 2 publications

(3 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is in accordance with observations by Carlson et al (34), but in contrast to the blunted PRL response to TRH after 36 hours of fasting found by Vinik et al (35).…”

Section: Andsupporting

confidence: 87%

Alterations in the morning plasma levels of hormones and the endocrine responses to bicycle exercise during prolonged strain. The significance of energy and sleep deprivation

Opstad

1991

Acta Endocrinologica

View full text Add to dashboard Cite

The relative significance of physical exercise, energy and sleep deprivation for the morning levels of hormones and the endocrine response to short-term bicycle exercise were investigated in 24 male cadets during a 5-day military training course. Significant increases in the morning levels of noradrenaline, adrenaline, and dopamine, and a decrease in PRL were ascribed mainly to physical strain. Cortisol and hGH increased, whereas insulin and glucose decreased mainly due to energy deficiency. Pulse rate after the bicycle test was unchanged and similar in all groups in spite of increased catecholamine responses. The increased catecholamine response was mainly due to physical strain. The cortisol response to the bicycle test was increased in all groups, and energy deficiency caused slower postexercise recovery. The incremental hGH response to the exercise test was unchanged in the energy-deficient subjects but abolished in the wellfed subjects. The results suggest that the endocrine responses during long-lasting exhausting strain were mainly due to physical exertion and energy deficiency, whereas sleep deprivation did not play any major role.Physical exercise is known to elicit a multitude of endocrine and metabolic responses appropriate for energy mobilization and cardiovascular adaptation. Thus, there is a gradual increase in the plasma levels of noradrenaline, adrenaline, dopamine and pulse rate with increasing exercise intensity (1,2). The serum levels of cortisol and growth hormone are known to increase when a certain workload is exceeded (3-6). Short-term physical exercise has variable effects on serum prolactin (7-10), and a decrease has been shown during long-term exereise (11). Serum insulin decreases during shortterm exercise, and glucose is slightly increased (10,12).Only moderate peripheral endocrine and meta¬ bolic alterations have been found during sleep deprivation (13). Cortisol, hGH and PRL have been shown to increase during night-time, but the dis¬ tinction between the effect of sleep and the natural circadian rhythm is difficult. It seems, however, as if sleep as such increases the serum levels of hGH and cortisol (13,14).In contrast to sleep deprivation, energy defi¬ ciency causes profound changes in the metabolic and endocrine state of the human body (15)(16)(17).There are alterations both in the secretion and degradation of hormones and metabolites. The action of hormones on target tissues is altered as are the energy stores. hGH and cortisol have been shown to increase during starvation, whereas the thyroid function is decreased (18,19).Previously, considerable endocrine and meta¬ bolic alterations have been documented during a 5-day military training course with heavy physical exercise, sleep and energy deficiency (10)(11)(12)14,20,21). Some of these results were found to be depen¬ dent on sleep and/or nutritional factors as studied in separate courses where the cadets were given either extra amounts of sleep or additional food supplies. In these courses, blood samples were drawn immediately ...

show abstract

“…This is in accordance with observations by Carlson et al (34), but in contrast to the blunted PRL response to TRH after 36 hours of fasting found by Vinik et al (35).…”

Section: Andsupporting

confidence: 87%

Alterations in the morning plasma levels of hormones and the endocrine responses to bicycle exercise during prolonged strain. The significance of energy and sleep deprivation

Opstad

1991

Acta Endocrinologica

View full text Add to dashboard Cite

show abstract

“…As phenothiazines are commonly used in anorexia nervosa and are known to elevate prolactin levels in this condition (Hafner et al. (Vinik et al 1974) and protein-calorie malnutrition (Becker et al 1975). The defect in peak prolactin secretion found in our study may therefore be secondary to starvation.…”

Section: Discussionmentioning

confidence: 98%

The effect of weight gain on gonadotrophins and prolactin in anorexia nervosa

Isaacs

Leslie

Gomez

et al. 1980

Acta Endocrinologica

View full text Add to dashboard Cite

Serum levels of gonadotrophins and prolactin and their response to luteinizing hormone/follicle stimulating hormone -releasing hormone (LRH) and thyrotrophin releasing hormone (TRH) were measured in 14 females with anorexia nervosa when at low body weight and again in 6 cases during, and 12 cases after weight gain. Mean serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels were low initially and whereas FSH increased significantly with weight gain, LH levels remained subnormal in most patients. LH responses to LRH were grossly impaired or absent in patients whose weight was below 75% of the ideal, but increased dramatically above this weight overshadowing the more modest increase in FSH response. In three patients, however, impaired LH responses persisted as ideal weight was approached. Basal prolactin levels were well within the normal range in all patients. During weight gain there was no change in basal levels but the prolactin level 20 min after TRH was significantly increased.

show abstract

“…Such a delay is strongly suggestive of hypothalamic dysfunction (Faglia et al, 1975;Hall et al, 1972). But diminished PRL responses to TRH are associated with protein-calorie malnutrition (Becker et al, 1975) and with experimental starvation (Vinik et al, 1974).…”

Section: Dynamic Testing Of Prl Secretionmentioning

confidence: 99%

The Physiology of eating disorders

Weiner¹

1985

Int. J. Eat. Disord.

View full text Add to dashboard Cite

This article summarizes current understanding of the pathophysiology of anorexia nervosa. Evidence is reviewed of alterations in hypothalamic‐pitui‐tary‐thyroid mechanisms, catecholamine metabolism, and endogenous opioid activity. It is concluded that once weight loss and starvation occur, the usual mechanisms for release and inhibition of various regulators of eating behavior change, and a new set of regulating mechanisms is instituted. Thus, despite an increased body of knowledge, understanding of the origins of anorexia nervosa still eludes us.

show abstract

Impaired Prolactin Response to Synthetic Thyrotropin-Releasing Hormone After a 36 Hour Fast

Cited by 21 publications

References 2 publications

Alterations in the morning plasma levels of hormones and the endocrine responses to bicycle exercise during prolonged strain. The significance of energy and sleep deprivation

Alterations in the morning plasma levels of hormones and the endocrine responses to bicycle exercise during prolonged strain. The significance of energy and sleep deprivation

The effect of weight gain on gonadotrophins and prolactin in anorexia nervosa

The Physiology of eating disorders

Contact Info

Product

Resources

About