The Pivotal Interaction Between Serotonin and Calcium Shifts in Lactating Pregnant Spanish Purebred Mares: The Aging Effect
by
, , , , , and
Katiuska Satué
1
,
Esterina Fazio
2,
Pietro Medica
2,*,
Maria Gemma Velasco-Martinez
1,
Cristina Cravana
2,
Giuseppe Bruschetta
2
and
Deborah La Fauci
2 1
Department of Animal Medicine and Surgery, Faculty of Veterinary, Cardenal Herrera-CEU University, 46115 Valencia, Spain
2
Unit of Veterinary Physiology, Department of Veterinary Sciences, Messina University, Polo Universitario Annunziata, 98168 Messina, Italy
*
Author to whom correspondence should be addressed.
Vet. Sci. 2025, 12(5), 398; https://doi.org/10.3390/vetsci12050398
Submission received: 13 January 2025
/
Revised: 6 March 2025
/
Accepted: 27 March 2025
/
Published: 23 April 2025
(This article belongs to the Section Veterinary Reproduction and Obstetrics)
Simple Summary
This is an experimental study carried out on thirty-one healthy lactating and pregnant Spanish Purebred mares to evaluate if, in equines, like other species, serotonin (5-HT) induces increased bone mobilization by augmenting calcium (Ca2+) concentrations in blood and milk during pregnancy and/or lactation. The hypothesis of this study was that plasma 5-HT and ionized (ICa2+) and total Ca2+ (TCa2+) could vary under pregnancy and lactation conditions in mares of advancing age, providing information not only from a physiological but also from a clinical point of view in the equine species. Positive relationships between circulating 5-HT and both ICa2+ and TCa2+, as well as between ICa2+ and TCa2+, were observed. Aging appears to reduce the secretory tone of 5-HT, with a concurrent large shift in Ca2+ metabolism in lactating pregnant mares.
Abstract
During the pregnancy and lactation phases, physiological adaptations occur in the mother to cope with the additional nutritional demands of the fetus and newborn. In experimental animals and cows, serotonin (5-HT) induces augmented bone mobilization by increasing calcium (Ca2+) concentrations in blood and milk during pregnancy and/or lactation. These interactions between 5-HT and Ca2+ homeostasis remain unknown in mares. Hence, the hypothesis of this study was that, as in other species, mares’ 5-HT and Ca2+ concentrations are influenced by pregnancy and lactation and that this relationship could be influenced by age. The aim was to verify the existence of a bidirectional interaction between circulating 5-HT and ionized (ICa2+) and total (TCa2+) Ca2+ shifts in thirty-one healthy lactating Spanish Purebred mares during pregnancy, evaluating the effect of different ages (<10- and >10 years old). Compared to >10-year-old mares, those aged <10 years old showed a greater 5-HT concentration from the 3rd to the 8th month of pregnancy (p < 0.05), a greater ICa2+ concentration from the 5th to the 8th month (p < 0.05), a lower TCa2+ concentration from the 1st to the 3rd month (p < 0.05), a greater concentration at the 7th, 8th, and 11th month (p < 0.05), and a greater ICa2+/TCa2+ ratio from the 5th to the 7th month (p < 0.05). The data obtained show an interesting and significant relationship between circulating 5-HT and both ICa2+ and TCa2+, as well as between ICa2+ and TCa2+. Moreover, aging appears to reduce the secretory tone of 5-HT, with a concurrent large shift in Ca2+ metabolism in lactating pregnant mares.
Keywords:
serotonin; ionized/total calcium; mares; pregnancy; lactation
