Hormonal regulation of phosphate homeostasis in goats during transition to rumination.
Regulatory processes in phosphorus (P) homeostasis in small ruminants are quite different compared to monogastric animals. Adaptive responses of modulating hormones [parathyroid hormone (PTH) and calcitriol] to feeding variable amounts of P are lacking. Therefore, the aim of this study was to examine the influence of high dietary P intake (control diet: 4 g kg(-1) dry matter; high-P diet: 8 g kg(-1) dry matter) on the expression levels of PTH receptor (PTHR), vitamin D receptor (VDR) and Na+-dependent Pi transporters (NaPi II) in kidney and jejunum of goats starting rumination. After 3 months of feeding, plasma phosphate (Pi) and PTH concentrations were increased in the high-P diet group, whereas calcium and calcitriol were not changed. The intestinal Na+-dependent Pi transport capacity was not influenced by a high-P diet and the expression of jejunal VDR, PTHR and NaPi IIb was not modified. Interestingly, renal Na+-dependent Pi transport capacity was significantly reduced and concomitantly the expression of PTHR and NaPi IIa was decreased. In conclusion, the adaptive response of renal Pi reabsorption in goats, which were in transition from non-ruminant to ruminant stage was comparable to that of monogastric animals. In contrast, the modulation of the intestinal Pi absorption was like in adult ruminants.
Muscher
Alexandra
A
Department of Physiology, School of Veterinary Medicine Hannover, Bischofsholer Damm 15/102, 30173, Hannover, Germany. alexandra.muscher@tiho-hannover.de
Hattendorf
Julia
J
Pfeffer
Ernst
E
Breves
Gerhard
G
Huber
Korinna
K
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001835:Body Weight; D002117:Calcitriol / Q000097:blood; D002118:Calcium / Q000097:blood; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004064:Digestive System / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D006041:Goats / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D006706:Homeostasis / Q000502:physiology*; D006728:Hormones / Q000097:blood / Q000502:physiology*; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism; D007583:Jejunum / Q000187:drug effects / Q000378:metabolism; D007672:Kidney Cortex / Q000187:drug effects / Q000378:metabolism; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood; D010758:Phosphorus / Q000097:blood / Q000378:metabolism*; D016226:Phosphorus, Dietary / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology; D044168:Receptor, Parathyroid Hormone, Type 1 / Q000235:genetics / Q000378:metabolism; D018167:Receptors, Calcitriol / Q000235:genetics / Q000378:metabolism; D050613:Sodium-Phosphate Cotransporter Proteins, Type IIa / Q000235:genetics / Q000378:metabolism; D050614:Sodium-Phosphate Cotransporter Proteins, Type IIb / Q000235:genetics / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D006728:Hormones; D010281:Parathyroid Hormone; D016226:Phosphorus, Dietary; D044168:Receptor, Parathyroid Hormone, Type 1; D018167:Receptors, Calcitriol; D050613:Sodium-Phosphate Cotransporter Proteins, Type IIa; D050614:Sodium-Phosphate Cotransporter Proteins, Type IIb; D010758:Phosphorus; D000469:Alkaline Phosphatase; D000254:Sodium-Potassium-Exchanging ATPase; D002117:Calcitriol; D002118:Calcium