Characteristics of prolactin-releasing response to salsolinol in vivo in cattle

Hashizume, T.; Sawada, T.; Yaegashi, T.; Saito, H.; Ezzat Ahmed, A.; Goto, Y.; Nakajima, Y.; Jin, J.; Kasuya, E.; Nagy, G.M.

doi:10.1016/j.domaniend.2010.01.002

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Volume 39, Issue 1 , Pages 21-25, July 2010

Characteristics of prolactin-releasing response to salsolinol in vivo in cattle

T. Hashizume
- Faculty of Agriculture, Iwate University, Morioka, Japan
- Corresponding author at: Faculty of Agriculture, Iwate University, Morioka 020-8550, Japan. Tel.: +81 19 621 6161; fax: +81 19 621 6161.
T. Sawada
- Faculty of Agriculture, Iwate University, Morioka, Japan
T. Yaegashi
- Faculty of Agriculture, Iwate University, Morioka, Japan
H. Saito
- Faculty of Agriculture, Iwate University, Morioka, Japan
A. Ezzat Ahmed
- Faculty of Agriculture, Iwate University, Morioka, Japan
Y. Goto
- Faculty of Agriculture, Iwate University, Morioka, Japan
Y. Nakajima
- Faculty of Agriculture, Iwate University, Morioka, Japan
J. Jin
- Faculty of Agriculture, Iwate University, Morioka, Japan
E. Kasuya
- Laboratory of Animal Neurophysiology, National Institute of Agrobiological Science, Tsukuba, Japan
G.M. Nagy
- Neuromorphological and Neuroedocrine Research Laboratory, Department of Human Morphology, Hungarian Academy of Science and Semmelweis University, Budapest, Hungary

Received 18 October 2009; received in revised form 30 December 2009; accepted 14 January 2010. published online 22 February 2010.

Abstract

The aims of the present study were to clarify the effect of salsolinol (SAL), a dopamine (DA)-derived endogenous compound, on the secretion of prolactin (PRL) in cattle. The experiments were performed from April to June using calves and cows. A single intravenous (i.v.) injection of SAL (5mg/kg body weight [BW]) or sulpiride (a DA receptor antagonist, 0.1mg/kg BW) significantly stimulated the release of PRL in male and female calves (P<0.05), though the response to SAL was smaller than that to sulpiride. The secretory pattern of PRL in response to SAL or sulpiride in female calves resembled that in male calves. A single i.v. injection of SAL or sulpiride significantly stimulated the release of PRL in cows (P<0.05). There was no significant difference in the PRL-releasing response between the SAL- and sulpiride-injected groups in cows. A single intracerebroventricular injection of SAL (10mg/head) also significantly stimulated the release of PRL in castrated calves (P<0.05). These results show that SAL is involved in the regulatory process for the secretion of PRL, not only in male and female calves, but also in cows. The results also suggest that the potency of the PRL-releasing response to SAL differs with the physiological status of cattle.