Sheng H P, Huggins R A
Growth. 1975 Mar;39(1):137-57.
Changes in total body and tissue composition of 43 beagles were analyzed from 0 day (birth) to 1 year. The tissues studied were skeletal muscle, viscera (heart, lungs, gut, liver, kidneys), skeleton, skin, and brain, and the data were expressed as follows: fat-free tissue weight (FFTW) as a per cent of total fat-free wet weight (FFWW); water and protein in grams per kilogram FFTW; and Na, Cl, K in milliequivalents FFTW. The mass of skeletal muscle increased from 21% of FFWW at birth to 36% at 1 year while the contribution of the remainder of the tissues decreased: skeleton from 30 to 25%, viscera 23 to 15%, skin 18 to 13%, and brain 4 to 0.9%. Over the same period, total body water decreased from 780 g/kg to 665, water of skeletal muscle from 771 to 665, of viscera from 782 to 621, of skeleton from 644 to 424, of skin from 765 to 669, of brain from 853 to 692; Total protein increased from 113 g/kg to 196, in skeletal muscle from 122 to 253, in viscera from 114 to 195, in skeleton from 71 to 112, in skin from 170 to 227, and in brain from 63 to 164. Total Na was 84 mEq/kg throughout the first year of growth, 101 for skeleton, and 89 for skin, while Na increased in viscera from 66 to 75 and in brain from 63 to 77, but decreased in skeletal muscle from 75 to 59. Total K increased from 31 mEq/kg at birth to 62 at 1 year, and from 38 to 107 in skeletal muscle, from 49 to 78 in viscera, and decreased from 27 to 11 in skin, and 42 to 122 in brain. Total Cl decreased from 58 to 49, in skeletal muscle from 52 to 34, in skeleton from 43 to 33, while that in viscera increased from 56 to 78. The contribution of skeletal muscle and viscera (the major metabolic cell mass) to total FFWW increased from 44 to 52%, and it contributed over 50% of total water, protein, Cl, and 89% of K. Skeletal muscle accounted for the increases. Skin and skeleton contributed 38% of FFWW, 17% of water, 29% of Na, 19% of Cl, 16% of protein, and 10% of K. The rates of change in these parameters fell into three patterns: (1) the content of the chemical component did not change significanly in the first year of growth; (2) it increased or decreased at a constant rate; or (3) there were two rates at which the concentration changed; the break between them occurred between the third and fourth months and coincided with evidence of increasing sexual maturation. A specific pattern of change was characteristic of a particular tissue and appeared independent of that of the total dog and other tissues. These data support the conclusion that there are mechanisms intrinsic to each tissue which exert a degree of control during growth over its chemical composition; therefore, growth itself can be considered an intrinsic regulatory mechanism.
分析了43只比格犬从出生0天到1岁时全身及组织组成的变化。所研究的组织包括骨骼肌、内脏（心脏、肺、肠道、肝脏、肾脏）、骨骼、皮肤和大脑，数据表示如下：无脂肪组织重量（FFTW）占总无脂肪湿重（FFWW）的百分比；每千克FFTW中的水和蛋白质克数；以及每千克FFTW中的钠、氯、钾毫当量数。骨骼肌质量从出生时占FFWW的21%增加到1岁时的36%，而其余组织的占比下降：骨骼从30%降至25%，内脏从23%降至15%，皮肤从18%降至13%，大脑从4%降至0.9%。在同一时期，全身水含量从780克/千克降至665克/千克，骨骼肌水含量从771克/千克降至665克/千克，内脏从782克/千克降至621克/千克，骨骼从644克/千克降至424克/千克，皮肤从765克/千克降至669克/千克，大脑从853克/千克降至692克/千克；总蛋白从113克/千克增加到至196克/千克，骨骼肌中从122克/千克增加到253克/千克，内脏中从114克/千克增加到195克/千克，骨骼中从71克/千克增加到112克/千克，皮肤中从170克/千克增加到227克/千克，大脑中从63克/千克增加到164克/千克。在生长的第一年，总钠含量始终为84毫当量/千克，骨骼中为101毫当量/千克，皮肤中为89毫当量/千克，而内脏中的钠从66毫当量/千克增加到75毫当量/千克，大脑中从63毫当量/千克增加到77毫当量/千克，但骨骼肌中的钠从75毫当量/千克降至至59毫当量/千克。总钾含量从出生时的31毫当量/千克增加到1岁时的62毫当量/千克，骨骼肌中从38毫当量/千克增加到107毫当量/千克，内脏中从49毫当量/千克增加到78毫当量/千克，皮肤中从27毫当量/千克降至11毫当量/千克，大脑中从42毫当量/千克增加到122毫当量/千克。总氯含量从58毫当量/千克降至49毫当量/千克，骨骼肌中从52毫当量/千克降至34毫当量/千克，骨骼中从43毫当量/千克降至33毫当量/千克，而内脏中的氯从56毫当量/千克增加到78毫当量/千克。骨骼肌和内脏（主要代谢细胞群）占总FFWW的比例从44%增加到52%，并且它们占总水、蛋白质、氯的50%以上，占钾的89%。增加的部分主要由骨骼肌引起。皮肤和骨骼占FFWW的38%，水的17%，钠的29%，氯的19%，蛋白质的16%，钾的10%。这些参数的变化速率分为三种模式：（1）化学成分含量在生长的第一年没有显著变化；（2）以恒定速率增加或减少；（3）浓度变化有两个速率；它们之间的转折点出现在第三个月和第四个月之间，与性成熟增加的证据一致。特定的变化模式是特定组织的特征，并且似乎独立于整个犬体和其他组织。这些数据支持以下结论：每个组织都有内在机制，在生长过程中对其化学成分发挥一定程度的控制作用；因此，生长本身可以被视为一种内在调节机制。
