RESUMO
We investigated the role of prolactin and suckling stimulation in the expression of maternal behaviour of primiparous rabbits. Bromocriptine (1 mg/kg/day), given to intact mothers across postpartum days 1-5, decreased serum concentrations of prolactin to undetectable levels, reduced crouching, and increased time inside the nest. Failure of maternal nest-building, provoked by bromocriptine injections from pregnancy day 26 to parturition or to postpartum day 5, correlated with a stronger reduction in crouching and an increased time inside the nest, measures of disturbed maternal behaviour, on postpartum days 3 and 5. Preventing suckling by thelectomy did not prevent prolactin release but reduced crouching incidence and increased the time spent inside the nest on postpartum days 3 and 5. Bromocriptine, injected in thelectomized mothers across postpartum days 1-5, further reduced the incidence of crouching and increased the time spent inside the nest on postpartum days 3 and 5. We conclude that prolactin acting prepartum facilitates maternal behaviour initiation in rabbits and, together with pup stimulation, maintains this behaviour across lactation.
Assuntos
Comportamento Materno/fisiologia , Prenhez/fisiologia , Prolactina/fisiologia , Coelhos/fisiologia , Animais , Bromocriptina/farmacologia , Feminino , Antagonistas de Hormônios/farmacologia , Trabalho de Parto/fisiologia , Lactação/efeitos dos fármacos , Comportamento Materno/efeitos dos fármacos , Atividade Motora/efeitos dos fármacos , Comportamento de Nidação/efeitos dos fármacos , Comportamento de Nidação/fisiologia , Mamilos/fisiologia , Feromônios/fisiologia , Gravidez , Prenhez/sangue , Prolactina/sangue , Fatores de TempoRESUMO
A sensitive radioimmunoassay for the measurement of TSH in the eluate of blood spotted on filter paper has been developed. The method is consistently sensitive to 0.1 to 0.25 muU of TSH and enables the detection of values equivalent to 6 to 15 muU/ml of serum. The measurement of TSH in the filter paper spot in all infants with low filter paper spot T4 has permitted rapid confirmation of 10 cases of neonatal hypothyroidism. However, cases of hypothalamic hypothyroidism with low or normal filter paper spot TSH concentrations would have been missed using only this method. Since these patients represent approximately 10% of our neonatal hypothyroid population, we do not recommend this method as a primary screening procedure, but rather as a confirmatory test which will accelerate the diagnosis and therefore the onset of therapy.