Effect of ACTH (tetracosactide) on steroid hormone levels in the mare

Hedberg, Ylva; Dalin, Anne-Marie; Forsberg, M.; Lundeheim, N.; Sandh, G.; Hoffmann, Bernd; Ludwig, Carsten; Kindahl, H.

doi:10.1016/j.anireprosci.2006.06.007

Cited by 31 publications

(7 citation statements)

References 38 publications

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“…However, the effect of OVX on cortisol is still controversial. Ovariectomy in humans leads to a reduction in cortisol synthesis and secretion via a reduction in adrenocorticotrophic hormone (ACTH) stimulation [48], while an ovariectomy in animals, such as mare, increases cortisol [49], which corresponds with our results. This discrepancy may be attributed to the differences in species, health status [50], stress condition [51], and the time the blood was collected, as cortisol levels fluctuate due to circadian rhythm behavior [52].…”

Section: Discussionsupporting

confidence: 88%

Omega-3-Rich Tuna Oil Derived from By-Products of the Canned Tuna Industry Enhances Memory in an Ovariectomized Rat Model of Menopause

Wattanathorn,

Thukham-Mee

2024

Antioxidants

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To increase the value of the by-products of the canned tuna industry, the memory enhancement effect and the possible mechanisms of omega-3-rich tuna oil in bilateral ovariectomized (OVX) rats were assessed. Female rats were orally given tuna oil at doses of 140, 200, and 250 mg/kg of body weight (BW) for 28 days before OVX and for 21 days continually after OVX. Memory performance was assessed every week, whereas the parameters regarding mechanisms of action were assessed at the end of the study. All doses of tuna oil enhanced memory, docosahexaenoic acid (DHA) levels, and superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities but decreased cortisol, acetylcholinesterase (AChE), malondialdehyde (MDA), and inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Medium and high doses of tuna oil suppressed monoamine oxidase (MAO) but increased eNOS activity. A high dose of tuna oil suppressed gamma-aminotransferase (GABA-T) but increased glutamic acid decarboxylase (GAD) and sirtuin-1. A medium dose of tuna oil decreased homocysteine (Hcys) and C-reactive protein. No change in telomere or estradiol was observed in this study. Our results suggest the memory-enhancing effect of tuna oil in an OVX rat model of menopause. The main mechanisms may involve a reduction in oxidative stress, inflammation, and neurotransmitter regulation.

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Section: Discussionsupporting

confidence: 88%

Omega-3-Rich Tuna Oil Derived from By-Products of the Canned Tuna Industry Enhances Memory in an Ovariectomized Rat Model of Menopause

Wattanathorn,

Thukham-Mee

2024

Antioxidants

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“…In the mare, the physiological status significantly alters CORT concentrations. Based on previous studies conducted in intact and ovariectomized mares, in which it was determined that the administration of synthetic analogue of ACTH (tetracosactide) stimulates the synthesis of CORT [89,90], Satué et al [91] described that in the natural estral cycle, the increase in ACTH secretion stimulates the synthesis of CORT at the time of ovulation in Spanish Purebred mares. However, Ginther et al [92] found increased levels of CORT during the luteal phase, followed by a decrease during the periovulatory period at the time of follicular deviation.…”

Section: Sexual Excitation and Reproductive Statementioning

confidence: 99%

“…Compared to the usual circadian pattern characterized by the morning increase of CORT in physiologically normal mares [37,45], CORT levels decrease in the morning [45] and increase at night [36] in ovariectomized mares. Pregnancy is considered an additional factor that modifies the diurnal and annual pattern of CORT [89,90], and can even mask cyclicality during the second half of pregnancy in the mare [32]. These changes in the acrofase are related to the action of the gestation and lactation hormones, exerting a different influence on the secretion and use of CORT in the mare.…”

Section: Sexual Excitation and Reproductive Statementioning

confidence: 99%

Action Mechanisms and Pathophysiological Characteristics of Cortisol in Horses

Ambrojo¹,

Corzano²,

Poggi³

2018

Corticosteroids

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Cortisol (CORT), also known as stress hormone, plays a vital role in physiological processes such as electrolyte and fluid balance, cardiovascular homeostasis, carbohydrate, protein and lipid metabolism, immune and inflammatory responses, and sexual development and reproduction. Cortisol levels are influenced by various physiological factors such as race, age, circadian rhythm, seasonality, exercise and pregnancy. Also, some stressful conditions including isolation or transport, among others, modify levels of this hormone in the body. Excesses or deficiencies of cortisol cause important clinical problems such as Cushing's and Addison's syndromes, which contribute substantially to morbidity in equine medicine. Thus, in this review, we will develop the mechanisms of synthesis and regulation, as well as the physiological factors involved and the most important diseases related to the alteration of cortisol secretion in horses and foals.

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“…The sex distribution of the groups was also a limitation of the study, but the only differences detected between the sexes were in plasma testosterone. In mares, testosterone and androstenedione are secreted from both the adrenals and the ovaries, and both are susceptible to ACTH stimulation and stage of the mare’s cycle ( 51 ), which was not accounted for in this study, whereas the only source of androgens in the gelding are the adrenals. There were no differences in cortisol metabolite excretion, plasma glucocorticoid concentrations, or gene expression by sex.…”

Section: Discussionmentioning

confidence: 96%

Dysregulation of Cortisol Metabolism in Equine Pituitary Pars Intermedia Dysfunction

et al. 2018

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Equine Cushing disease [pituitary pars intermedia dysfunction (PPID)] is a common condition of older horses, but its pathophysiology is complex and poorly understood. In contrast to pituitary-dependent hyperadrenocorticism in other species, PPID is characterized by elevated plasma ACTH but not elevated plasma cortisol. In this study, we address this paradox and the hypothesis that PPID is a syndrome of ACTH excess in which there is dysregulation of peripheral glucocorticoid metabolism and binding. In 14 horses with PPID compared with 15 healthy controls, we show that in plasma, cortisol levels and cortisol binding to corticosteroid binding globulin were not different; in urine, glucocorticoid and androgen metabolites were increased up to fourfold; in liver, 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) expression was reduced; in perirenal adipose tissue, 11β-HSD1 and carbonyl reductase 1 expression was increased; and tissue cortisol levels were not measurably different. The combination of normal plasma cortisol with markedly enhanced urinary cortisol metabolite excretion and dysregulated tissue-specific steroid-metabolizing enzymes suggests that cortisol clearance is increased in horses with PPID. We infer that the ACTH excess may be compensatory and pituitary pathology and autonomous secretion may be a secondary rather than primary pathology. It is possible that successful therapy in PPID may be targeted either at lowering ACTH or, paradoxically, at reducing cortisol clearance.

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Effect of ACTH (tetracosactide) on steroid hormone levels in the mare

Cited by 31 publications

References 38 publications

Omega-3-Rich Tuna Oil Derived from By-Products of the Canned Tuna Industry Enhances Memory in an Ovariectomized Rat Model of Menopause

Omega-3-Rich Tuna Oil Derived from By-Products of the Canned Tuna Industry Enhances Memory in an Ovariectomized Rat Model of Menopause

Action Mechanisms and Pathophysiological Characteristics of Cortisol in Horses

Dysregulation of Cortisol Metabolism in Equine Pituitary Pars Intermedia Dysfunction

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