Effects of induced thyroid deficiency on the development of suckling behavior in rats

Increased testis growth and sperm production in adult rats following transient neonatal goitrogen treatment: optimization of the propylthiouracil dose and effects of methimazole

“…In the studies in which hypothyroidism in the neonates was induced by adding PTU to the mother's water, a wide variety of concentrations ranging from 0.1 to 0.01% have been used (Meisami, 1984;Blake and Henning, 1985;Tamasy et al, 1986;Behnam-Rassoli et al, 1991), and the relationship between the PTU concentration given in the mother's water and the ultimate degree of hypothyroidism in the pups has been determined (Blake and Henning, 1985). One (Henning, 1978;Narayanan et al, 1982;Blake and Henning, 1985; (Palmero et al, 1989;Francavilla et al, 1991 …”

Evaluation and Characterization of the Hypothyroid <i>hyt/hyt </i>Mouse I: Somatic and Behavioral Studies

“…In the mouse and rat, autonomous fetal thyroid hormone secretion rises after 16-17 days postconception followed by early neonatal in creases in T4 and subsequently T3. These increases in T4 have been shown to be temporally correlated with somatic development, brain differentiation, and behavioral deve lopment in the rat [11].The hypothyroid neonatal rat demonstrated somatic [8,16,17,29], neuroanatomical [11,12], electrophysiological [11,14] and behavioral abnormalities [7,9,10,14,17,19,22,24,27] [7,10,14,24] and hyperactivity [7,9,27] have been observed. Abnormalities in adaptive learned behavior [7,10,14,17,27] have been seen in more mature rats following neonatal or fetal hypothyroidism.…”

“…Abnormalities in adaptive learned behavior [7,10,14,17,27] have been seen in more mature rats following neonatal or fetal hypothyroidism. The hypo thyroid rats have also shown delayed vestibular system de velopment [ 12] and delayed and abnormal cerebellar devel opment and delayed cerebral cortical myelination and diffe rentiation [11,23].However, most of the behavioral and anatomical data has come from postnatal rodent hypothyroidism, resulting from surgically produced [ 17] or pharmacologically induced [7,9,10,22,27] hypothyroidism. The pharmacological agents employed to produce both fetal and neonatal hypo thyroidism such as propylthiouracil (PTU) [9,10,22,27] and methimazole [7] may have independent effects as well as causing both maternal and fetal hypothyroidism when given in utero [II].…”

“…Previous research on the appearance and subsequent disappearance of reflexive behaviors suggested that these behaviors provided the foun dation for normal motor development in rodent and human 13, 22], Cliff avoidance, surface righting, and negative geo taxis were some of the normal behaviors that ontogenically develop in the rodent soon after birth [1][2][3]. The time of their appearance and their presence have been suggested for a role in the normal development of the rodent nervous sys tem and for the subsequent appearance of more complex behaviors [22,28]. Our demonstration of delays in cliff avoi dance and negative geotaxis reflexive behavior was similar to what had been observed in the fetal and neonatal hypo thyroid rat [22], The development of rooting and suckling behavior which preceded normal neonatal feeding behavior [22] and other reflexes including the placing response, body righting response, and ventral suspension [14] have also been shown in neonatal hypothyroidism.…”

Signal Transduction Processes in the Developing Brain: Perturbations of G Protein Alpha-Subunit Abundances by Perinatal Hypothyroidism

“…It has been reported that maternal hypothyroidism may affect fetal development indirectly by altering maternal metabolism such that fetal nutrition is compromised [29][30][31]. Moreover milk secretion by lactating dams and suckling behaviour of neonates may be altered by hypothyroidism [32,33]. As a reassurance we made measurements of the main metabolic fuels in plasma (table 1).…”