Hokao R, Saito T R, Takahashi K W
Imamichi Institute for Animal Reproduction, Ibaraki, Japan.
Jikken Dobutsu. 1993 Oct;42(4):579-83. doi: 10.1538/expanim1978.42.4_579.
It is known that suppression of copulatory behavior observed in aged male animals is due to elevate prolactin levels, the so-called hyperprolactinemia, found in these animals. The present study was done to determine whether hyperprolactinemia can modify the copulatory behavior of young adult male rats. Hyperprolactinemia was induced by grafting one or two pituitary glands of adult males of the same strain under the kidney capsules of each sexually experienced male. Grafted animals exhibited suppressed copulatory behavior patterns when tested one month after pituitary transplantation. The animals given two pituitary grafts differed from the sham-operated controls in latency to intromit (P < 0.05), as well as in the numbers of intromission (P < 0.05) and ejaculation (P < 0.01). After tests of copulatory behavior, serum concentrations of LH, FSH, prolactin and testosterone were measured by radioimmunoassay. Serum levels of prolactin were significantly increased (P < 0.05) in the animals given 2 grafts, compared with sham-operated controls. From these results, suppression of copulatory behavior in the young adult animals grafted was similar to that in aged adults. The findings suggest that decline of copulatory behavior with increasing age results from chronic elevation of prolactin.
已知在老年雄性动物中观察到的交配行为抑制是由于这些动物体内催乳素水平升高，即所谓的高催乳素血症。本研究旨在确定高催乳素血症是否会改变年轻成年雄性大鼠的交配行为。通过将同一品系成年雄性的一个或两个垂体移植到每只性经验丰富的雄性大鼠的肾囊下诱导高催乳素血症。垂体移植一个月后进行测试时，移植动物表现出交配行为模式受到抑制。接受两个垂体移植的动物与假手术对照组相比，插入潜伏期（P < 0.05）、插入次数（P < 0.05）和射精次数（P < 0.01）均存在差异。在进行交配行为测试后，通过放射免疫测定法测量血清中促黄体生成素（LH）、促卵泡生成素（FSH）、催乳素和睾酮的浓度。与假手术对照组相比，接受两个移植的动物血清催乳素水平显著升高（P < 0.05）。从这些结果来看，移植的年轻成年动物的交配行为抑制与老年动物相似。这些发现表明，随着年龄增长交配行为的下降是由催乳素的长期升高导致的。
