Dietary nitrogen and calcium modulate CYP27B1 expression in young goats

Wilkens, Mirja R.; Elfers, Kristin; Schmicke, Marion; Breves, Gerhard; Muscher-Banse, Alexandra S.

doi:10.1016/j.domaniend.2018.03.005

Cited by 13 publications

(7 citation statements)

References 37 publications

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“…A positive correlation between IGF1 concentration and CYP27B1 expression was shown, underlining the impact of IGF1 on CYP27B1 synthesis and therefore circulating levels of calcitriol (11) .…”

mentioning

confidence: 76%

Modulation of growth hormone receptor-insulin-like growth factor 1 axis by dietary protein in young ruminants

Firmenich¹,

Schnepel²,

Hansen³

et al. 2019

Br J Nutr

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A reduced protein intake causes a decrease in insulin-like growth factor 1 (IGF1) concentrations and modulates Ca homoeostasis in young goats. IGF1 is synthesised by the liver in response to stimulation by growth hormone (GH). Due to rumino-hepatic circulation of urea, ruminants are suitable for investigating the effects of protein reduction despite sufficient energy intake. The present study aimed to investigate the impact of a protein-reduced diet on the expression of components of the somatotropic axis. Male young goats were divided into two feeding groups receiving either a control diet (20 % crude protein (CP)) or a reduced-protein diet (9 % CP). Blood concentrations of IGF1 and GH were measured, and a 24-h GH secretion profile was compiled. Moreover, ionised Ca and insulin concentrations as well as mRNA and protein expression levels of hepatic proteins involved in GH signalling were quantified. Due to the protein-reduced diet, concentrations of ionised Ca, insulin and IGF1 decreased significantly, whereas GH concentrations remained unchanged. Expression levels of the hepatic GH receptor (GHR) decreased during protein reduction. GHR expression was down-regulated due to diminished insulin concentrations as both parameters were positively correlated. Insulin itself might be reduced due to reduced blood Ca levels that are involved in insulin release. The protein-reduced diet had an impact on the expression of components of the somatotropic axis as a disruption of the GH-IGF1 axis brought about by diminished GHR expression was shown in response to a protein-reduced diet.

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mentioning

confidence: 76%

Modulation of growth hormone receptor-insulin-like growth factor 1 axis by dietary protein in young ruminants

Firmenich¹,

Schnepel²,

Hansen³

et al. 2019

Br J Nutr

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“…Uncoupling of this somatotropic axis indicated by low IGF1 plasma concentrations was observed during dietary protein restriction in growing goats and in peripartum dairy cows (Muscher et al, 2011;Piechotta et al, 2014). Reduced IGF1 was associated with decreased expression of CYP27B1 and affected bone mobilisation and intestinal Ca absorption probably via diminished plasma concentrations of 1,25-(OH) 2 D 3 (Wilkens et al, 2018).…”

Section: Endocrine Control Of Calcium and Phosphate Transportmentioning

confidence: 98%

“…In Table 1 we present data from balance studies carried out in different ruminant species to illustrate that Ca and P absorption and secretion out of and into different gastrointestinal segments as well as urinary excretion are influenced by age, lactation and type of diet. There is inconsistency in the contribution of the forestomach of ruminants to overall Ca absorption (Table 1), which can partly be explained with differences in the composition of rations as mineral homeostasis interferes with other dietary factors such as dietary cation-anion difference, Mg and CP supply (Goff, 2008;Muscher and Huber, 2010;Elfers et al, 2016a;Wilkens et al, 2018). Therefore, studies using a more mechanistic approach are an important tool to enhance our knowledge.…”

Section: Introductionmentioning

confidence: 99%

Review: Regulation of gastrointestinal and renal transport of calcium and phosphorus in ruminants

Wilkens¹,

Muscher-Banse²

2020

Animal

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In comparison to monogastric animals, ruminants show some peculiarities in respect to the regulation of mineral homeostasis, which can be regarded as a concerted interplay between gastrointestinal absorption, renal excretion and bone mobilisation to maintain physiological Ca and phosphate (Pi) concentrations in serum. Intestinal absorption of Ca or Pi is mediated by two general mechanisms: paracellular, passive transport dominates when luminal Ca or Pi concentrations are high and transcellular. The contribution of active transport becomes more important when dietary Ca or Pi supply is restricted or the demand increased. Both pathways are modulated directly by dietary interventions, influenced by age and regulated by endocrine factors such as 1,25-dihydroxyvitamin D3. Similar transport processes are observed in the kidney. After filtration, Ca and Pi are resorbed along the nephron. However, as urinary Ca and Pi excretion is very low in ruminants, the regulation of these renal pathways differs from that described for monogastric species, too. Furthermore, salivary secretion, as part of endogenous Pi recycling, and bone mobilisation participate in the maintenance of Ca and Pi homeostasis in ruminants. Saliva contains large amounts of Pi for buffering rumen pH and to ensure optimal conditions for the rumen microbiome. The skeleton is a major reservoir of Ca and Pi to compensate for discrepancies between demand and uptake. But alterations of the regulation of mineral homeostasis induced by other dietary factors such as a low protein diet were observed in growing ruminants. In addition, metabolic changes, for example, at the onset of lactation have pronounced effects on gastrointestinal mineral transport processes in some ruminant species. As disturbances of mineral homeostasis do not only increase the risk of the animals to develop other diseases, but are also associated with protein and energy metabolism, further research is needed to improve our knowledge of its complex regulation.

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“…A lack of calcitriol production is an important factor in dairy cows susceptible to milk fever after parturition (Goff et al, 1989). Diminished calcitriol synthesis (Wilkens et al 2018), leading to reduced levels of blood Ca by downregulating renal Ca transporting proteins. Reduced intake of feed and protein around parturition might be comparable to the conditions for the young goats receiving an N-reduced feeding in the present study.…”

Section: Discussionmentioning

confidence: 99%

Modulation of renal calcium and phosphate transporting proteins by dietary nitrogen and/or calcium in young goats1

Firmenich¹,

Elfers²,

Wilkens³

et al. 2018

Journal of Animal Science

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In young goats, a reduction in dietary nitrogen (N) had an impact on mineral homeostasis although ruminants are able to recycle N effectively due to rumino-hepatic circulation. A solitary calcium (Ca) reduction stimulated calcitriol synthesis and Ca concentrations remained unchanged, whereas a dietary N reduction led to a decrease in calcitriol, which could not be prevented by a simultaneous reduction of N and Ca. In a previous study, it was shown that a reduced dietary N intake caused a decrease in intestinal Ca absorption due to a reduction of intestinal Ca transporting proteins. As no data on the potential role of the kidneys are available, it was the aim of the present study to evaluate whether an N- and/or Ca-reduced diet had an impact on renal Ca and phosphate (Pi) transporting protein expression in young goats. The animals were divided into 4 feeding groups, each receiving an adequate N and Ca supply, a reduced N supply, a reduced Ca supply, or a combined N and Ca reduction for 6 to 9 wk. The protein expression of the renal Ca channel transient receptor potential cation channel subfamily V member 5 (TRPV5) was diminished in N-reduced fed goats (P = 0.03), whereas in Ca restricted animals, the expression remained unaltered. The mRNA and protein expression of the Ca-binding protein calbindin-D28K (CaBPD28K) and the sodium-Ca exchanger 1 (NCX1) were significantly decreased due to the N-reduced feeding (mRNA, P = 0.003; P < 0.0001; protein, P = 0.002; P = 0.02), whereas dietary Ca reduction increased the CaBPD28K and NCX1 mRNA expression (P = 0.05; P = 0.01). The mRNA and protein expression of the parathyroid hormone receptor (PTHR) decreased due to the N-reduced feeding (P = 0.02; P = 0.03). These results confirm that a reduced dietary N intake led to decreased TRPV5, CaBPD28K, PTHR, and NCX1 expression levels, contributing to low levels of calcitriol and plasma Ca. In contrast to this, sodium-phosphate cotransporter type IIa expression and plasma Pi concentration were increased during dietary N reduction, thus indicating that Pi homeostasis is modulated in a calcitriol-independent manner. In conclusion, the modulation of Ca transporting proteins expression in the kidney is not able to prevent changes in mineral homeostasis in young goats receiving an N-reduced diet.

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Dietary nitrogen and calcium modulate CYP27B1 expression in young goats

Cited by 13 publications

References 37 publications

Modulation of growth hormone receptor-insulin-like growth factor 1 axis by dietary protein in young ruminants

Modulation of growth hormone receptor-insulin-like growth factor 1 axis by dietary protein in young ruminants

Review: Regulation of gastrointestinal and renal transport of calcium and phosphorus in ruminants

Modulation of renal calcium and phosphate transporting proteins by dietary nitrogen and/or calcium in young goats1

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