Prolactin and thyroid hormones

V CASTILLO; J LALIA; C SCODELLARO; MJ BELLINI.; C GOBELLO

ANALECTA VETERINARIA

FACULTAD DE CIENCIAS VETERINARIAS, UNIVERSIDAD NACIONAL DE LA PLATA

Lugar: LA PLATA; Año: 2010 vol. 30 p. 5 - 7

Estrogen neuroprotection has been shown in pathological conditions damaging the hippocampus, such as trauma, aging, neurodegeneration, excitotoxicity, oxidative stress, hypoglycemia, amyloid-b peptide exposure and ischemia. Hypertensive encephalopathy also targets the hippocampus; therefore, hypertension seems an appropriate circumstance to evaluate steroid neuroprotection. Two experimental models of hypertension, the spontaneously hypertensive rats (SHR) and deoxycorticosterone (DOCA)-salt hypertensive rats, develop hippocampal abnormalities, which include decreased neurogenesis in the dentate gyrus, astrogliosis, low expression of brain derived neurotrophic factor (BDNF) and decreased number of neurons in the hilar region, with respect of their normotensive Abstract: There is very scarce information concerning prolactin (PRL) serum concentrations under pathologic conditions in dogs. To describe the relationship between PRL and thyroid hormones serum concentrations forty-five cross- and pure-bred male and female dogs with clinical suspicious of hypothyroidism were blood sampled for PRL and thyrotropin (TSH), thyroxin (T4) and/or free T4 (FT4) serum determinations. Prolactin concentrations in hypothyroid and euthyroid dogs were compared by the Mann-Whitney test. For further description of data correlation analyses between PRL and TSH, FT4 or T4 were also tested. Percentage PRL change was calculated in the patient in which the TRH stimulation test was carried out. Overall serum PRL concentrations in hypothyroid (n= 34) and euthyroid (n= 11) dogs were 25.9±4.8 and 14.6±6.5 ng/ml, respectively (p >0.05). No significant correlation could be found between PRL and the different thyroid hormones in any group. The stimulated dog was classified as subclinical a hypothyroid (grade I). Prolactin increased 5 times (from 0.4 to 2.1 ng/ ml) after TRH injection in this animal. Further work should be done to describe prolactinemia in canine hypothyroidism.