Granz S, Ellendorff F, Grossmann R, Kato Y, Mühlbauer E, Elsaesser F
Institute for Animal Husbandry and Animal Behaviour (FAL), Neustadt, Germany.
J Neuroendocrinol. 1997 Jun;9(6):439-49. doi: 10.1046/j.1365-2826.1997.00599.x.
The mechanism underlying the ontogenetic increase in plasma growth hormone (GH), luteinizing hormone (LH) and follicle stimulating hormone (FSH) concentration during fetal life in mammalian species and the prenatal sex difference in these hormones in some species is not fully understood. To this end anterior pituitaries were collected from German Landrace fetuses and piglets at day (d) 50, 65, 80, 95, 110 pc and d 6 pp and pituitary GH, LH beta, FSH beta and alpha-subunit mRNA levels were determined by measuring Northern blot hybridization signals. GH mRNA was detected in both sexes as early as d 50 pc. The mRNA level markedly increased with age in both sexes (males > females, P < or = 0.05) reaching its maximum at d 95/110 pc. LH beta mRNA signals were first detected at d 50 pc in females and at d 65 pc in males increasing thereafter to a maximum at d 6 pp in both sexes (P < or = 0.05). In males the augmentation in LH beta mRNA was delayed compared to females (P < or = 0.01). Before d 80 pc no FSH beta mRNA hybridization signals were apparent. Thereafter the mRNA level continuously increased with age (P < or = 0.01) in both sexes reaching its maximum at d 6 pp. The FSH beta mRNA level in females was always higher than in males (P < or = 0.01). As early as d 50 pc the alpha-subunit mRNA level was high in both sexes and further increased without sex difference to d 6 pp (P < or = 0.05). In conclusion, the mRNA levels of GH, LH beta and FSH beta are age and sex dependent during fetal development. We suggest that the fetal increase in plasma GH concentration can be accounted for by changes in GH mRNA levels, while the dramatic perinatal decrease in plasma GH concentration seems to be primarily controlled at the posttranslational and/or secretion level. The fetal sex difference and the increase in plasma LH and FSH concentrations seems to be primarily dependent on the cellular concentration of the gonadotropin beta-subunit mRNAs and/or number of gonadotrophs.
哺乳动物胎儿期血浆生长激素（GH）、促黄体生成素（LH）和促卵泡激素（FSH）浓度个体发育性增加的机制以及某些物种中这些激素的产前性别差异尚未完全明确。为此，采集了德国长白猪胎儿和仔猪在妊娠50天、65天、80天、95天、110天以及出生后6天的垂体，通过检测Northern印迹杂交信号来测定垂体GH、LHβ、FSHβ和α亚基的mRNA水平。早在妊娠50天时，两性均检测到GH mRNA。mRNA水平在两性中均随年龄显著增加（雄性>雌性，P≤0.05），在妊娠95/110天时达到最高。LHβ mRNA信号最早在雌性妊娠50天时检测到，在雄性妊娠65天时检测到，此后在两性中均在出生后6天时增加到最高（P≤0.05）。与雌性相比，雄性中LHβ mRNA的增加延迟（P≤0.01）。在妊娠80天之前，未出现明显的FSHβ mRNA杂交信号。此后，mRNA水平在两性中均随年龄持续增加（P≤0.01），在出生后6天时达到最高。雌性中的FSHβ mRNA水平始终高于雄性（P≤0.01）。早在妊娠50天时，两性中的α亚基mRNA水平就很高，并且在出生后6天时无性别差异地进一步升高（P≤0.05）。总之，在胎儿发育过程中，GH、LHβ和FSHβ的mRNA水平与年龄和性别有关。我们认为，胎儿期血浆GH浓度的增加可由GH mRNA水平的变化来解释，而围产期血浆GH浓度的急剧下降似乎主要在翻译后和/或分泌水平受到控制。胎儿性别差异以及血浆LH和FSH浓度的增加似乎主要取决于促性腺激素β亚基mRNA的细胞浓度和/或促性腺细胞数量。
