Publications (2)6.84 Total impact
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Article: Induction of brain prolactin receptor long-form mRNA expression and maternal behavior in pup-contacted male rats: promotion by prolactin administration and suppression by female contact.
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ABSTRACT: Prolactin (PRL) is considered to induce maternal behavior toward foster young in female rats. In the present study, we studied the relationship between pup contact-induced maternal behavior and serum PRL concentrations and brain PRL receptor (PRL-R) mRNA expression in male rats. Both intact and castrated male rats exposed to foster pups gradually developed caretaking behavior such as crouching and licking, but their exhibitions of other maternal behavior components, retrieval/grouping and nest building, were incomplete. However, in the male rats displaying crouching and licking, the concomitant increases in serum PRL concentration and brain mRNA expression for long-form PRL-R were observed. The expression of short-form PRL-R mRNA in the brain was not stimulated by pup contact. Administration of PRL remarkably promoted the onset of those maternal responses in male rats. On the other hand, when an intact male rat was housed in a cage where a lactating female rat and her pups were living, his scores in maternal behavior tests toward pups were lowered. And, concomitantly, increases in serum PRL concentration and brain expression of long-form PRL-R mRNA were reduced. In castrated male rats, however, the ratings of maternal behavior toward foster young, serum PRL concentration increase, or brain long-form PRL-R mRNA expression were not reduced at all by cohabitation with a female and her pups. These findings indicated that maternal behavior was triggered and maintained in pup-contacted male rats through elevated serum PRL levels and induced brain long-form PRL-R.Neuroendocrinology 07/1996; 63(6):559-68. · 2.38 Impact Factor -
Article: Restraint stress enhances the gene expression of prolactin receptor long form at the choroid plexus.
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ABSTRACT: Hormonal control of brain functions is considered to be important in the tolerance of stress, and it is now established that stress elevates serum PRL levels in male or cycling female rats. To investigate whether or how serum PRL acts on the brain during exposure to stress, we analyzed serum PRL levels and the gene expression of brain PRL receptors in rats subjected to restraint stress in the water (RSW). The serum PRL concentration was remarkably increased within 30 min in the rats by exposure to RSW and decreased to the initial level after 4 h of RSW, remaining at this level for up to 7 h of RSW. After the rats were released from the stress, the serum PRL level was significantly lowered in 6 h. Ribonuclease protection assay and in situ hybridization analysis revealed that messenger RNA (mRNA) expression for the long form PRL receptor [PRL-R(L)] was remarkably induced in the rat choroid plexus in 2 h of RSW. The high expression level of PRL-R(L) mRNA in the region was reduced after the rats were released from the stress. PRL-R(L) mRNA expression in the hypothalamus was at lower levels than those in the choroid plexus before and during the RSW treatment. The short form PRL receptor mRNA expression in the rat brain was considerably lower than expression of the long form receptor mRNA before or during RSW. The results indicated that the restraint stress caused a rapid increase in serum PRL and induced the gene expression for PRL-R(L) in the choroid plexus, suggesting stress-induced and choroid plexus PRL-R(L)-mediated transport of serum PRL into the cerebrospinal fluid.Endocrinology 01/1996; 136(12):5608-13. · 4.46 Impact Factor
